Transcriptomic response of Anopheles gambiae sensu stricto mosquito larvae to Curry tree (Murraya koenigii) phytochemicals

Large-scale performance assessment of the BG-Counter 2 used with two different mosquito traps

BACKGROUND

Mosquitoes are important vectors of pathogens. They are usually collected with CO2-baited traps and subsequently identified by morphology. This procedure is very time-consuming. Automatic counting traps could facilitate timely evaluation of the local risk for mosquito-borne pathogen transmission or decision-making on vector control measures, but the counting accuracy of such devices has rarely been validated in the field.

METHODS

The Biogents (BG)-Counter 2 automatically counts mosquitoes by discriminating the size of captured objects directly in the field and transmits the data to a cloud server. To assess the accuracy of this counting device, 27 traps were placed at 19 sampling sites across Germany and used in daily, weekly or bimonthly intervals from April until October 2021. The BG-Counter 2 was attached to a CO2-trap (BG-Pro trap = CO2-Pro) and the same trap was converted to also attract gravid mosquitoes (upside-down BG-Pro trap with a water container beneath = CO2-Pro-gravid). All captured mosquitoes were identified by morphology. The number of females (unfed and gravid), mosquito diversity and the number of identified specimens in relation to the counting data of the BG-Counter were compared between the two trapping devices to evaluate sampling success and counting accuracy.

RESULTS

In total 26,714 mosquitoes were collected during 854 trap days. The CO2-Pro-gravid trap captured significantly more mosquitoes per trap day for all specimens, gravid females and non-gravid females, while there was no difference in the mosquito diversity. The linear model with the captured mosquitoes as a response and the counted specimens as a predictor explained only a small degree of the variation within the data (R2 = 0.16), but per individual trap the value could reach up to 0.62 (mean R2 = 0.23). The counting accuracy for the daily samples had a significant positive correlation with sample size, resulting in higher accuracy for the CO2-Pro-gravid trap and higher accuracy for sites and sampling months with high mosquito abundance.

CONCLUSIONS

While the accuracy of the BG-Counter 2 is quite low, the device is able to depict mosquito phenology and provide information about local population dynamics.

Identification and genotyping of Echinococcus granulosus from human clinical samples in Guilan province, north of Iran

Cystic echinococcosis (CE) is a significant health problem in both human and veterinary medicine. It is caused by the tapeworm Echinococcus granulosus (E. granulosus). The objective of this study was to investigate molecular diversity of E. granulosus from the paraffin-embedded human (FFPE) tissue samples using sequencing of mitochondrial genes. Thirty-five FFPE tissue samples were collected from different regions of Guilan province, north of Iran. Demographic data were recorded using a questionnaire. Five sections (1 mm) of the tissue were prepared and deparaffined using xylene and ethanol methods. Molecular analysis was performed using the Nad1 and Cox1 genes using PCR and DNA sequencing. Totally, 25 cases (71.43%) were women and 10 cases (28.57%) were men. The most affected age group was 21-30 yr old. The most of cysts were isolated from the liver (n = 19; 54.29%) and others in the lung (n = 16; 45.71%). The Cox1 and Nad1 genes were successfully amplified in 16 (45.71%) and 12 (34.28%) DNA samples from FFPE tissue. Sequencing analysis revealed that all samples were E. granulosus sensu stricto complex (G1 and G3). In this study, E. granulosus sensu stricto complex G1 and G3 were identified in human hydatid cysts and showed the presence of sheep/dog cycle in human infection. This finding confirmed and completed previous studies on the geospatial distribution of E. granulosus sensu stricto complex G1 and G3 in the southern and coastal areas of the Caspian Sea region.

Understanding the research and practical needs required to control toxocariasis in Iran

Human toxocariasis (HT) is a widespread zoonotic infection globally, notably prevalent in tropical areas. Enhancing our understanding of toxocariasis can lead to increased attention towards the socioeconomic impact and control of this neglected zoonosis. We conducted a comprehensive review of all available articles and official documents on toxocariasis in Iran to identify research gaps and critical needs for its control. This review highlights that despite numerous studies exploring various aspects of toxocariasis in definitive and paratenic hosts, as well as humans and environmental contamination, significant data deficiencies and gaps persist across different regions in the country. These gaps involve investigating the worm burden and reinfection rates in definitive hosts, developing more sensitive methods to detect and differentiate of Toxocara species, and understanding the behavior of definitive host animals. Additionally, identifying potential paratenic hosts for HT and exploring the organ-specific affinity and survival duration of Toxocara larvae within these hosts are essential areas for exploration. It's also imperative to comprehend the sylvatic and domestic cycles of the parasite in paratenic hosts. Furthermore, assessing egg density in the environment, exploring potential new sources such as water, and identifying regions with optimal climatic conditions for the survival and development of Toxocara eggs are crucial for the formulation of effective prevention and control strategies. Identifying at-risk groups, developing early diagnosis techniques, employing imaging methods, and identifying long-term complications in humans are also crucial. Community health organizations should prioritize health education for the public and professionals. Furthermore, accurately estimating definitive host populations, monitoring and preventing their movements in public places, implementing regular deworming practices for pets and stray hosts, and recognizing the infection's significance as a health priority are critical. This comprehensive understanding advocates for a holistic "one health" approach to control of HT.

Exploring the Efficacy of Pellitorine as an Antiparasitic Agent Against Argulus: Impacts on Antioxidant Levels and Immune Responses in Goldfish (Carassius auratus)

INTRODUCTION

Argulus spp. infestation is a significant challenge for aquaculture, currently, there are no approved medications available to efficiently manage this parasite. Consequently, mechanical removal of parasites using forceps and natural substances like herbs are being explored as alternative treatment methods. Pellitorine (PLE) is a naturally occurring compound found in several plant species. It is classified as an alkaloid and belongs to the class of compounds known as amides.

MATERIALS AND METHODS

This study aimed to evaluate the effectiveness of PLE in preventing Argulus spp. infestations in goldfish (Carassius auratus) and to determine the optimal dosage of PLE for the detachment of Argulus spp.

RESULTS

The findings of this study revealed that PLE enhanced the immune response of goldfish by promoting superoxide dismutase (SOD) and catalase (CAT) in Argulus-infected goldfish. Additionally, PLE induces reactive oxygen species (ROS) generation and cellular damage in the Argulus. PLE at a dosage of 5 mg/mL was able to detach 80% of the argulus from goldfish within 12 h. Therapeutic index was found to be 5.99, suggesting that PLE is the safest drug.

CONCLUSIONS

Therefore, our findings suggest that PLE can be a suitable and effective treatment option for preventing Argulus infestations in goldfish. The results of this study can guide the use of PLE at an optimal dosage to control Argulus infestation in goldfish.

Higher outdoor mosquito density and Plasmodium infection rates in and around malaria index case households in low transmission settings of Ethiopia: Implications for vector control

BACKGROUND

Understanding the clustering of infections for persistent malaria transmission is critical to determining how and where to target specific interventions. This study aimed to determine the density, blood meal sources and malaria transmission risk of anopheline vectors by targeting malaria index cases, their neighboring households and control villages in Arjo-Didessa, southwestern Ethiopia.

METHODS

An entomological study was conducted concurrently with a reactive case detection (RCD) study from November 2019 to October 2021 in Arjo Didessa and the surrounding vicinity, southwestern Ethiopia. Anopheline mosquitoes were collected indoors and outdoors in index case households and their surrounding households (neighboring households), as well as in control households, using pyrethrum spray cache (PSC) and U.S. Centers for Disease Control and Prevention (CDC) light traps. Adult mosquitoes were morphologically identified, and speciation in the Anopheles gambiae complex was done by PCR. Mosquito Plasmodium infections and host blood meal sources were detected by circumsporozoite protein enzyme-linked immunosorbent assay (CSP-ELISA) and cytochrome b-based blood meal PCR, respectively.

RESULTS

Among the 770 anopheline mosquitoes collected, An. gambiae sensu lato (A. gambiae s.l.) was the predominant species, accounting for 87.1% (n = 671/770) of the catch, followed by the Anopheles coustani complex and Anopheles pharoensis, which accounted for 12.6% (n = 97/770) and 0.26% (n = 2/770) of the catch, respectively. From the sub-samples of An. gambiae s.l.analyzed with PCR, An. arabiensis and Anopheles amharicus were identified. The overall mean density of mosquitoes was 1.26 mosquitoes per trap per night using the CDC light traps. Outdoor mosquito density was significantly higher than indoor mosquito density in the index and neighboring households (P = 0.0001). The human blood index (HBI) and bovine blood index (BBI) of An. arabiensis were 20.8% (n = 34/168) and 24.0% (n = 41/168), respectively. The overall Plasmodium sporozoite infection rate of anophelines (An. arabiensis and An. coustani complex) was 4.4% (n = 34/770). Sporozoites were detected indoors and outdoors in captured anopheline mosquitoes. Of these CSP-positive species for Pv-210, Pv-247 and Pf, 41.1% (n = 14/34) were captured outdoors. A significantly higher proportion of sporozoite-infected mosquitoes were caught in index case households (5.6%, n = 8/141) compared to control households (1.1%, n = 2/181) (P = 0.02), and in neighboring households (5.3%, n = 24/448) compared to control households (P = 0.01).

CONCLUSIONS

The findings of this study indicated that malaria index cases and their neighboring households had higher outdoor mosquito densities and Plasmodium infection rates. The study also highlighted a relatively higher outdoor mosquito density, which could increase the potential risk of outdoor malaria transmission and may play a role in residual malaria transmission. Thus, it is important to strengthen the implementation of vector control interventions, such as targeted indoor residual spraying, long-lasting insecticidal nets and other supplementary vector control measures such as larval source management and community engagement approaches. Furthermore, in low transmission settings, such as the Arjo Didessa Sugarcane Plantation, providing health education to local communities, enhanced environmental management and entomological surveillance, along with case detection and management by targeting of malaria index cases and their immediate neighboring households, could be important measures to control residual malaria transmission and achieve the targeted elimination goals.

A scoping review on tsetse fly blood meal sources and its assay methods since 1956 to 2022

BACKGROUND

Tsetse flies (Glossina spp.) are the definitive biological vectors of African trypanosomes in humans and animals. Controlling this vector is the most promising method of preventing trypanosome transmission. This requires a comprehensive understanding of tsetse biology and host preference to inform targeted design and management strategies, such as the use of olfaction and visual cues in tsetse traps. No current review exists on host preference and blood meal analyses of tsetse flies.

METHODS

This review presents a meta-analysis of tsetse fly blood meal sources and the methodologies used to identify animal hosts from 1956 to August 2022. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRIMA-ScR) was applied. This focused on tsetse-endemic countries, blood meal analysis methodologies and the blood meal hosts identified. The articles were retrieved and screened from databases using predetermined eligibility criteria.

RESULTS

Only 49/393 of the articles retrieved matched the inclusion criteria. Glossina's main hosts in the wild included the bushbuck, buffalo, elephant, warthog, bushpig and hippopotamus. Pigs, livestock and humans were key hosts at the domestic interface. The least studied species included Glossina fuscipleuris, G. fusca, G. medicorum, G. tabaniformis and G. austeni. In the absence of preferred hosts, Glossina fed opportunistically on a variety of hosts. Precipitin, haemagglutination, disc diffusion, complement fixation, ELISA and PCR-based assays were used to evaluate blood meals. Cytochrome b (Cyt b) was the main target gene in PCR to identify the vertebrate hosts.

CONCLUSIONS

Tsetse blood meal sources have likely expanded because of ecological changes that could have rendered preferred hosts unavailable. The major approaches for analysing tsetse fly blood meal hosts targeted Cyt b gene for species identification by Sanger sequencing. However, small-fragment DNAs, such as the mammalian 12S and 16S rRNA genes, along with second- and third-generation sequencing techniques, could increase sensitivity for host identification in multiple host feeders that Sanger sequencing may misidentify as "noise". This review of tsetse fly blood meal sources and approaches to host identification could inform strategies for tsetse control.

Neofunctionalization driven by positive selection led to the retention of the loqs2 gene encoding an Aedes specific dsRNA binding protein

BACKGROUND

Mosquito borne viruses, such as dengue, Zika, yellow fever and Chikungunya, cause millions of infections every year. These viruses are mostly transmitted by two urban-adapted mosquito species, Aedes aegypti and Aedes albopictus. Although mechanistic understanding remains largely unknown, Aedes mosquitoes may have unique adaptations that lower the impact of viral infection. Recently, we reported the identification of an Aedes specific double-stranded RNA binding protein (dsRBP), named Loqs2, that is involved in the control of infection by dengue and Zika viruses in mosquitoes. Preliminary analyses suggested that the loqs2 gene is a paralog of loquacious (loqs) and r2d2, two co-factors of the RNA interference (RNAi) pathway, a major antiviral mechanism in insects.

RESULTS

Here we analyzed the origin and evolution of loqs2. Our data suggest that loqs2 originated from two independent duplications of the first double-stranded RNA binding domain of loqs that occurred before the origin of the Aedes Stegomyia subgenus, around 31 million years ago. We show that the loqs2 gene is evolving under relaxed purifying selection at a faster pace than loqs, with evidence of neofunctionalization driven by positive selection. Accordingly, we observed that Loqs2 is localized mainly in the nucleus, different from R2D2 and both isoforms of Loqs that are cytoplasmic. In contrast to r2d2 and loqs, loqs2 expression is stage- and tissue-specific, restricted mostly to reproductive tissues in adult Ae. aegypti and Ae. albopictus. Transgenic mosquitoes engineered to express loqs2 ubiquitously undergo developmental arrest at larval stages that correlates with massive dysregulation of gene expression without major effects on microRNAs or other endogenous small RNAs, classically associated with RNA interference.

CONCLUSIONS

Our results uncover the peculiar origin and neofunctionalization of loqs2 driven by positive selection. This study shows an example of unique adaptations in Aedes mosquitoes that could ultimately help explain their effectiveness as virus vectors.

The potential immunomodulatory effect of levamisole in humans and farm animals

This study conducted a literature review to investigate the immunomodulatory effect of levamisole in both humans and farm animals. The following procedure was followed for database searching: PubMed, Google Scholar, Web of Science, and Cochrane Library. All research works were updated to September 2022. The terms used in the literature search were included: ("levamisole" OR "immunity" OR "immune system") AND ("adjuvant" OR "fish" OR "poultry" OR "farm animal" OR "cattle" OR "sheep"). The current review enlightens the extensive potential of levamisole as an adjuvant immunotherapeutic agent and explains its divergent applications beyond its antiparasitic use as an adjuvant, dietary supplement, immunostimulant, antiviral, and anti-cancer drug in humans and farm animals. In the articles examined, various mechanisms have been proposed for levamisole immunoprotective effects, but hormonal alteration and stress hormone reduction are indicated as the main mechanisms in various animal species.

Mathematical modeling of malaria transmission dynamics in humans with mobility and control states

Malaria importation is one of the hypothetical drivers of malaria transmission dynamics across the globe. Several studies on malaria importation focused on the effect of the use of conventional malaria control strategies as approved by the World Health Organization (WHO) on malaria transmission dynamics but did not capture the effect of the use of traditional malaria control strategies by vigilant humans. In order to handle the aforementioned situation, a novel system of Ordinary Differential Equations (ODEs) was developed comprising the human and the malaria vector compartments. Analysis of the system was carried out to assess its quantitative properties. The novel computational algorithm used to solve the developed system of ODEs was implemented and benchmarked with the existing Runge-Kutta numerical solution method. Furthermore, simulations of different vigilant conditions useful to control malaria were carried out. The novel system of malaria models was well-posed and epidemiologically meaningful based on its quantitative properties. The novel algorithm performed relatively better in terms of model simulation accuracy than Runge-Kutta. At the best model-fit condition of 98% vigilance to the use of conventional and traditional malaria control strategies, this study revealed that malaria importation has a persistent impact on malaria transmission dynamics. In lieu of this, this study opined that total vigilance to the use of the WHO-approved and traditional malaria management tools would be the most effective control strategy against malaria importation.

Molecular characterization of MyD88 as a potential biomarker for pesticide-induced stress in Bombyx mori

The widespread use of pesticides hampers the immune system of non-target organisms, however, there is a lack of common biomarkers to detect such effects. Myeloid differentiation primary response factor 88 (MyD88) is a crucial junction protein in the Toll-like receptor signaling pathway, which plays an important role in the inflammatory response. In this study, we investigated MyD88 as a potential biomarker for pesticide-induced stress. Phylogenetic analysis revealed that MyD88 was a conserved protein in the evolution of vertebrates and invertebrates. MyD88s usually have death domain (DD) and Toll/interleukin-1 receptor (TIR) domain. Bombyx mori (B. mori) is an important economic insect that is sensitive to toxic substances. We found microbial pesticides enhanced the expression level of MyD88 in B. mori. Transcriptome analysis demonstrated that MyD88 expression level was increased in the fatbody after dinotefuran exposure, a third-generation neonicotinoid pesticide. Moreover, the expression of MyD88 was upregulated in fatbody and midgut by imidacloprid, a first-generation neonicotinoid pesticide. Additionally, insect growth regulator (IGR) pesticides, such as methoprene and fenoxycarb, could induce MyD88 expression in the fatbody of B. mori. These results indicated that MyD88 is a potential biomarker for pesticide-induced stress in B. mori. This study provides novel insights into screening common biomarkers for multiple pesticide stresses and important implications for the development of more sustainable pest management strategies.

First field and laboratory evaluation of LAMP assay for malaria diagnosis in Cubal, Angola

BACKGROUND

Malaria is a globally distributed infectious disease. According to the World Health Organization, Angola is one of the six countries that account for over half the global malaria burden in terms of both malaria cases and deaths. Diagnosis of malaria still depends on microscopic examination of thin and thick blood smears and rapid diagnostic tests (RDTs), which often lack analytical and clinical sensitivity. Molecular methods could overcome these disadvantages. The aim of this study was to evaluate, for the first time to our knowledge, the performance of a loop-mediated isothermal amplification (LAMP) for the diagnosis of malaria in an endemic area in Cubal, Angola, and to assess the reproducibility at a reference laboratory.

METHODS

A total of 200 blood samples from patients attended at Hospital Nossa Senhora da Paz, Cubal, Angola, were analysed for Plasmodium spp. detection by microscopy, RDTs, and LAMP. LAMP assay was easily performed in a portable heating block, and the results were visualized by a simple colour change. Subsequently, the samples were sent to a reference laboratory in Spain to be reanalysed by the same colorimetric LAMP assay and also in real-time LAMP format.

RESULTS

In field tests, a total of 67/200 (33.5%) blood samples were microscopy-positive for Plasmodium spp., 98/200 RDT positive, and 112/200 (56%) LAMP positive. Using microscopy as reference standard, field LAMP detected more microscopy-positive samples than RDTs (66/67; 98% vs. 62/67; 92.5%). When samples were reanalysed at a reference laboratory in Spain using both colorimetric and real-time assays, the overall reproducibility achieved 84.5%.

CONCLUSIONS

This is the first study to our knowledge in which LAMP has been clinically evaluated on blood samples in a resource-poor malaria-endemic area. The colorimetric LAMP proved to be more sensitive than microscopy and RDTs for malaria diagnosis in field conditions. Furthermore, LAMP showed an acceptable level of reproducibility in a reference laboratory. The possibility to use LAMP in a real-time format in a portable device reinforces the reliability of the assay for molecular diagnosis of malaria in resource-poor laboratories in endemic areas.

Proteomics identification of overexpressed serum proteins in dogs with Babesiacanis infection

Background and Aim

Canine babesiosis, caused by the protozoan parasite Babesia canis, is characterized by clinical manifestations, including hemolytic anemia, thrombocytopenia, multiple organ failure, and may result in death. This disease is detected using conventional blood smears, which are time-consuming and have low sensitivity. This study aimed to investigate a more rapid and sensitive method for detecting B. canis infection in dogs by examining the expressed serum protein profiles using proteomics.

Materials and Methods

We collected six sera samples from three healthy and three B. canis-infected dogs diagnosed using blood smear and polymerase chain reaction. We analyzed the proteins using two-dimensional gel electrophoresis. The candidate spots from the gel were subjected to protein identification using a nano-liquid chromatography system coupled to an ion-trap mass spectrometer equipped with an electrospray ionization nano-sprayer.

Results

We found that 10 protein spots were overexpressed in the serum samples from infected dogs compared with healthy dogs, which corresponded to three proteins: serotransferrin, serotransferrin isoforms X1, and hemopexin. Furthermore, analysis of the protein-protein interaction network confirmed that they strongly interacted with each other.

Conclusion

This study suggests that high levels of serotransferrin and hemopexin are related to B. canis infection, making these proteins potential candidates for the development of diagnostic molecules or vaccines.

Avian malaria parasite infections do not affect personality in the chestnut thrush (Turdus rubrocanus) on the Qinghai-Tibet Plateau

Personality traits, the consistent individual behavioral differences, are currently gaining much attention in studies of natural bird populations. However, associations between personality traits and parasite infections are not often investigated. Even less attention has been given to studies of birds in the high-elevation region such as the Tibetan plateau. This research aims to examine the relationship between avian malaria parasites and two personality traits in a population of the Chestnut Thrush (Turdus rubrocanus) breed in the Tibetan plateau. Our results revealed no evidence of sex bias in malaria parasite prevalence. Furthermore, we found no effect of infection status on two personality scores: activity and boldness. Additionally, no effects on the activity level or boldness were observed for different parasite lineages of Haemoproteus, Leucocytozoon, the sex of the birds, or their interactions. Similarly, we did not find any relationship between activity level and boldness with nestling numbers, sex, or their interactions. Notably, individuals with a larger number of offspring tended to display greater boldness. Our findings indicate that blood parasite infections are common in this population but do not significantly impact the personality of the birds.

Climate Change and Aging Health in Developing Countries

The climate of the Earth has changed throughout history. Climate change negatively impacts human rights in a wide range of ways. The study aims to find out the impact of climate change on aging health in developing countries. The study found that public health will be devastated if climate change continues unabated. Countries that are least responsible for global warming are most susceptible to the effects of higher temperatures, such as death and disease. In low- and middle-income countries, disasters are more likely to happen to people aged 60 and over. Although climate change affects all of us, older people are especially at risk from it, as evidenced by a growing body of research. The study also offers countermeasures and suggestions to develop aging health in developing countries affected by climate change.

The in vitro and in vivo effects of Lucilia sericata larval secretions on Leishmania major

The emerging of drug resistant against Leishmania parasites prompts scientists to seek for novel therapeutic strategies against theses infectious protozoan parasites. Among different strategies, the use of larvae secretions could be suggested as a possible therapy with low side effects. Accordingly, the current study evaluated the in vitro and in vivo effects of Lucilia sericata larval secretions on Leishmania major, the causative agent of cutaneous leishmaniasis (CL). After preparation of L. sericata larval stages (L2 and L3) secretions, the potential effects of secretions were evaluated against L. major promastigotes and amastigotes (in vitro) using MTT assay. The cytotoxicity effects of secretions were also checked on uninfected macrophages. In addition, in vivo experiments were also conducted to investigate the effects of larvae's secretions on the CL lesions induced in the BALB/c mice. Although the increased concentration of larvae secretions exhibited a direct effect on the promastigotes proliferation (viability), contrarily, L2 secretions at a concentration of 96 μg/ml represented the highest inhibitory effect on parasite (amastigotes) burden in infected macrophages. Interestingly, L3 secretions > 60 μg/ml induced inhibitory effects on amastigotes. The results relevant to the cytotoxicity effects of L2 and L3 secretions on uninfected-macrophages showed a dose dependent correlation. In vivo results were also significant, compared to the positive control group. This study suggested the plausible inhibitory effects of L. sericata larvae's secretions on the L. major amastigotes and CL lesions progression. It seems that the characterization of all effective components/proteins in the larvae secretions and their specific targets in parasite structure or in cell (macrophage) responses could further reveal more details regarding the anti-leishmanial properties of these compounds.

Overwintering Culex torrentium in abandoned animal burrows as a reservoir for arboviruses in Central Europe

Culex pipiens s.s./Culex torrentium belong to the most widespread mosquito taxa in Europe and are the main vectors of Sindbis, West Nile and Usutu virus. The adult overwintering females can act as reservoir for these arthropod-borne viruses (arboviruses), thus contributing to their local persistence when transmission cycles are interrupted during the winter. However, the main overwintering sites of Cx. torrentium are unknown. In a study from 2017, 3455 Cx. pipiens s.s./Cx. torrentium specimens were collected from abandoned animal burrows in Poznan, Poland. These specimens were retrospectively identified to species-level with a PCR assay, which revealed Cx. torrentium as dominant species (> 60%). Motivated by these results, we conducted a field study from February to July 2022 to systematically analyse the overwintering site patterns of Cx. pipiens s.s./Cx. torrentium. Mosquitoes were sampled using pipe traps in abandoned animal burrows (n = 20) and with aspirators in nearby anthropogenic overwintering sites (n = 23). All Cx. pipiens s.s./Cx. torrentium were screened for Flaviviridae RNA. In total, 4710 mosquitoes of five different taxa were collected from anthropogenic sites. 3977 of them were identified as Cx. p. pipiens/Cx. torrentium (Cx. p. pipiens: 85%, Cx torrentium: 1%, pools with both species: 14%). In contrast, only Cx. p. pipiens/Cx. torrentium (1688 specimens) were collected from animal burrows dominated by Cx. torrentium (52%), followed by pools with both species (40%) and Cx. p pipiens (8%). A single pool of 10 Cx. torrentium specimens collected from an animal burrow was positive for Usutu virus. The detection of Usutu virus demonstrates that Cx. torrentium can act as winter reservoir for arboviruses. Abandoned animal burrows may by the primary overwintering site for the species and should be considered in future surveillance programmes, when sampling overwintering mosquitoes.

Trypanosomes infection, endosymbionts, and host preferences in tsetse flies (Glossina spp.) collected from Akagera park region, Rwanda: A correlational xenomonitoring study

Akagera National Park and its surroundings are home to tsetse flies and a number of their mammalian hosts in Rwanda. A One-health approach is being used in the control and surveillance of both animal and human trypanosomosis in Rwanda. Determination of the infection level in tsetse flies, species of trypanosomes circulating in vectors, the source of tsetse blood meal and endosymbionts is crucial in understanding the epidemiology of the disease in animals and humans in the region. Tsetse flies (n = 1101), comprising Glossina pallidipes (n = 771) and Glossina morsitans centralis (n = 330) were collected from Akagera park and surrounding areas between May 2018 and June 2019. The flies were screened for trypanosomes, vertebrate host DNA to identify sources of blood meal, and endosymbionts by PCR - High Resolution Melting analysis and amplicon sequencing. The feeding frequency and the feeding indices (selection index - W) were calculated to identify the preferred hosts. An overall trypanosome infection rate of 13.9% in the fly's Head and Proboscis (HP) and 24.3% in the Thorax and Abdomen (TA) were found. Eight trypanosome species were identified in the tsetse fly HP and TA, namely: Trypanosoma (T.) brucei brucei, T. congolense Kilifi, T. congolense savannah, T. vivax, T. simiae, T. evansi, T. godfreyi, T. grayi and T. theileri. We found no evidence of human-infective T. brucei rhodesiense. We also identified eighteen species of vertebrate hosts that tsetse flies fed on, and the most frequent one was the buffalo (Syncerus caffer) (36.5%). The frequently detected host by selection index was the rhinoceros (Diceros bicornis) (W = 16.2). Most trypanosome infections in tsetse flies were associated with the buffalo blood meal. The prevalence of tsetse endosymbionts Sodalis and Wolbachia was 2.8% and 4.8%, respectively. No Spiroplasma and Salivary Gland Hypertrophy Virus were detected. These findings implicate the buffaloes as the important reservoirs of tsetse-transmitted trypanosomes in the area. This contributes to predicting the main cryptic reservoirs and therefore guiding the effective control of the disease. The study findings provide the key scientific information that supports the current One Health collaboration in the control and surveillance of tsetse-transmitted trypanosomosis in Rwanda.

Digital PCR: modern solution to parasite diagnostics and population trait genetics

The use of polymerase chain reaction (PCR)-based diagnostic approaches has steadily increased in the field of parasitology in recent decades. The most recent large-scale technological modification of the PCR formula, also known as third-generation PCR, came in the form of digital PCR (dPCR). Currently, the most common form of dPCR on the market is digital droplet PCR (ddPCR). Unlike quantitative real-time PCR (qPCR), the digital format allows for highly sensitive, absolute quantification of nucleic acid targets and does not require external standards to be included in the developed assays. Dividing each sample into thousands of compartments and using statistical models also eliminates the need for technical replicates. With unprecedented sensitivity and enforcement of binary endpoint reactions, ddPCR not only allows the use of tiny sample volumes (especially important when working with limited amounts of DNA) but also minimises the impact of variations in amplification efficiency and the presence of inhibitors. As ddPCR is characterised by excellent features such as high throughput, sensitivity and robust quantification, it is widely used as a diagnostic tool in clinical microbiology. Due to recent advances, both the theoretical background and the practical, current applications related to the quantification of nucleic acids of eukaryotic parasites need to be updated. In this review, we present the basics of this technology (particularly useful for new users) and consolidate recent advances in the field with a focus on applications to the study of helminths and protozoan parasites.

Haematological indices and immune response profiles in dogs naturally infected and co-infected with Dirofilaria repens and Babesia canis

Co-infections with Dirofilaria repens and Babesia canis are rarely reported in the literature and there is very limited knowledge of their impact on canine health. Central Poland is endemic for both parasites, posing a risk of co-infections in dogs. To evaluate the impact of co-infection with B. canis and D. repens on canine health, four groups of dogs were examined: healthy dogs, dogs infected with B. canis, dogs infected with D. repens and dogs co-infected with both species. Blood parameters indicative of anaemia, kidney and liver damage were analysed statistically. Additionally, expression levels of immune response genes were quantified and compared, to define the type of immune response typically encountered in single- and co-infections. In dogs infected with D. repens, no major alterations in blood parameters were observed. Dogs infected with B. canis suffered from anaemia, kidney and liver insufficiency. In contrast, dogs co-infected with D. repens and B. canis showed milder alternation in blood biochemical parameters associated with liver (ALP activity) and kidney (serum urea and creatinine levels) dysfunction, compared to dogs infected only with B. canis. The expression of genes associated with cellular (Th1-mediated) (STAT4 and INF-γ), humoral (Th2-mediated) (STAT6, GATA3, SOCS3, IL-13) and regulatory (IL-10) responses was quantified. For this analysis, dogs infected with B. canis were divided into two groups-'Babesia 1' (mild babesiosis), 'Babesia 2' (severe babesiosis). All the tested factors, except INF-γ, were found to be expressed in dogs infected with D. repens. In 'Babesia 1' dogs, expression of GATA3 was highest, while in 'Babesia 2'-INF-γ and SOCS3 dominated. IL-13 expression was predominant in dogs infected with D. repens, and STAT6 and IL-10 predominated in dogs with co-infections.

Parasitological and histopathological studies to the effect of aqueous extract of Moringa oleifera Lam. leaves combined with praziquantel therapy in modulating the liver and spleen damage induced by Schistosoma mansoni to male mice

This study assessed the effectiveness of an aqueous extract of Moringa Oleifera Lam. leaves (MOL) alone or in combination with praziquantel (PZQ) drug targeting-infected mice with Schistosoma mansoni-induced liver and spleen damage. Mice were divided into eight groups control mice group treated orally with saline. PZQ group: non-infected mice treated orally with 300 mg/kg bwt PZQ three consecutive days. MOL group: non-infected mice treated orally with 150 mg/kg bwt MOL extract for 15 days. PZQ/ MOL group: non-infected mice treated orally with 300 mg/kg bwt PZQ for three consecutive days and 150 mg/kg bwt MOL extract for 15 days. IF group: infected mice with 100 cercariae/mouse of the Egyptian strain of S. mansoni. IF/PZQ group infected mice with S. mansoni cercariae and treated orally with 300 mg/kg bwt PZQ for three consecutive days. IF/MOL group: infected mice with S. mansoni cercariae treated orally with 150 mg/kg bwt MOL extract for 15 days. IF/PZQ +MOL group: infected mice with S. mansoni cercariae treated orally with 300 mg/kg bwt PZQ for three consecutive days and 150 mg/kg bwt MOL extract for 15 days. Blood, liver, spleen, worm, and eggs were collected at the end of the experimental period. Treatment of infected mice with MOL and PZQ together significantly reduced the number of ova/g tissue and eliminated the parasites. In addition, the liver and spleen of infected mice showed less histopathological alteration and immunohistochemical expression of nuclear factor kappa β (NF-Kβ). We can conclude that MOL extract combined with PZ has a curative effect on S. mansoni infection and helped to lessen its pathological effects.

Coxiella burnetii and its risk factors in cattle in Egypt: a seroepidemiological survey

Animal production is greatly affected by Q fever. As a result of a lack of methodology and financial means to perform extensive epidemiological surveys, the disease's underdiagnosis has proven to be a challenge for effective control. The present study aimed to determine the seroprevalence of C. burnetii in cattle raising in four governorates situated at Nile Delta of Egypt and assess the associated risk factors for infection. A total of 480 serum samples were collected from cattle and examined for presence of anti-C. burnetii antibodies using indirect ELISA assay. The overall seroprevalence of C. burnetii among examined cattle was 19.8%, with the Qalyubia governorate having the highest prevalence. The results of multivariable logistic regression analysis revealed significant association between C. burnetii seropositivity and age, communal grazing and/or watering, contact with small ruminants and history of infertility. According to the findings of this work, C. burnetii is circulating among cattle living in Nile Delta. It is suggested that adequate hygiene procedures and biosecurity measures should be implemented to limit the transmission of pathogens within cow herds and potential human exposure.

Species richness of bat flies and their associations with host bats in a subtropical East Asian region

BACKGROUND

Understanding the interactions between bat flies and host bats offer us fundamental insights into the coevolutionary and ecological processes in host-parasite relationships. Here, we investigated the identities, host specificity, and patterns of host association of bat flies in a subtropical region in East Asia, which is an understudied region for bat fly research.

METHODS

We used both morphological characteristics and DNA barcoding to identify the bat fly species found on 11 cavernicolous bat species from five bat families inhabiting Hong Kong. We first determined the phylogenetic relationships among bat fly species. Then, we elucidated the patterns of bat-bat fly associations and calculated the host specificity of each bat fly species. Furthermore, we assembled the mitogenomes of three bat fly species from two families (Nycteribiidae and Streblidae) to contribute to the limited bat fly genetic resources available.

RESULTS

We examined 641 individuals of bat flies and found 20 species, of which many appeared to be new to science. Species of Nycteribiidae included five Nycteribia spp., three Penicillidia spp., two Phthiridium spp., one Basilia sp., and one species from a hitherto unknown genus, whereas Streblidae included Brachytarsina amboinensis, three Raymondia spp., and four additional Brachytarsina spp. Our bat-bat fly association network shows that certain closely related bat flies within Nycteribiidae and Streblidae only parasitized host bat species that are phylogenetically more closely related. For example, congenerics of Raymondia only parasitized hosts in Rhinolophus and Hipposideros, which are in two closely related families in Rhinolophoidea, but not other distantly related co-roosting species. A wide spectrum of host specificity of these bat fly species was also revealed, with some bat fly species being strictly monoxenous, e.g. nycteribiid Nycteribia sp. A, Phthiridium sp. A, and streblid Raymondia sp. A, while streblid B. amboinensis is polyxenous.

CONCLUSIONS

The bat fly diversity and specificity uncovered in this study have shed light on the complex bat-bat fly ecology in the region, but more bat-parasite association studies are still needed in East Asian regions like China as a huge number of unknown species likely exists. We highly recommend the use of DNA barcoding to support morphological identification to reveal accurate host-ectoparasite relationships for future studies.

Plasmodium malariae contributes to high levels of malaria transmission in a forest-savannah transition area in Cameroon

BACKGROUND

Malaria control efforts are highly skewed towards Plasmodium falciparum while overlooking other Plasmodium species such as P. malariae. A better understanding of the role of Plasmodium species other than P. falciparum is needed to strengthen malaria elimination initiatives. The aim of the present study was to elucidate the contribution of P. malariae to malaria transmission in Cameroon.

METHODS

The study was conducted in the Ngatti Health District, a forest-savannah transition area in the Adamawa Region, Cameroon. A total of 497 individuals aged from 1 to 85 years were diagnosed with malaria in November 2020 using a rapid diagnostic test (RDT) and microscopy. Adult mosquitoes were collected between September 2019 and March 2020 by indoor aspiration and identified morphologically and molecularly. The infection status of Plasmodium spp. was also determined by quantitative PCR, and dried blood spots were collected from 156 participants with the aim to detect different Plasmodium species by nested PCR.

RESULTS

The overall Plasmodium prevalence was 50.3%, 51.8% and 64.7%, as detected by microscopy, the RDT and PCR, respectively. Based on the PCR results, P. falciparum was the most prevalent species (43%); followed by co-infections P. falciparum/P. malariae (17%), P. falciparum/P. ovale (1.3%), P. falciparum/P. ovale/P. malariae (1.3%); and then by P. malariae mono-infection (2.5%). The same trend was observed using microscopy, with 35% of participants infected with P. falciparum, 11% co-infected with P. falciparum/P. malariae and 4% infected with P. malariae. The prevalence and parasite density of malaria infection varied significantly with age group (P < 0.05), with the highest prevalence rate observed in children aged 6-10 years (P = 0.0001) while the density of Plasmodium infection increased significantly in children aged < 5 years compared to the other age groups (P = 10-3). Among the 757 Anopheles mosquitoes collected, 737 (97.35%) were An. funestus sensu stricto, 15 (1.9%) were An. gambiae and 5 (0.6%) were An. hancocki. The Plasmodium species recorded at the head/thorax level were P. falciparum and P. malariae, with a sporozoite infection rate of 8.4%; the highest sporozoite infection rate was recorded at Mibellon village (13.6%).

CONCLUSION

The results of this study reveal the significant contribution of P. malariae, in addition to P. falciparum, to the high malaria transmission rate in this region. These findings highlight the need to deploy initiatives to also tackle this Plasmodium species to eliminate malaria in the region.

Hygiene practices and factors influencing intestinal parasites among food handlers in the province of Belgarn, Saudi Arabia

Background

This study aimed to evaluate the association between socio-demographic status, and hygienic habits among food handlers with intestinal parasitic infections.

Methods

It was a cross-sectional study in which 112 participants were recruited, from Belgarn province of Saudi Arabia. The descriptive analysis was used to evaluate demographic data and categorical variables. The association between sociodemographic characteristics and Relative Risk regression analysis was performed for each investigated factor. p-value of <0.05, was assumed to be statistically significant.

Results

One hundred and twelve food handlers with a mean age of 33.5 ± 9.2 years were included in this study. The food handlers were from 15 different countries (11 Asians and four Africans). The majority of the food handlers were cooks (87, 77.7%), and waiters and dish washers (24, 21.4%). Among them, 106 (94.6%) used uniforms, and gloves at work. In hand washing practices, 104 (92.9%) wash their hands with soap before handling and preparing food and eight (7.1%) wash without soap, 98 (87.5%) wash with soap before meals and 14 (12.5%) wash without soap, 105 (93.8%) wash with soap after visiting toilets and seven (6.2%) wash without soap. Twenty-five (42.3%) of infected food handlers are not used to trim their fingernails. Intestinal infection was observed in 59 (52.68%) participants with mean age (32.5 ± 8.1 years) for infected participants.

Conclusion

In this study, food handlers had a high prevalence of intestinal parasites. Although some of the food handlers had a high level of education, the infection with intestinal parasites was detected. In addition to regular screening for intestinal parasites among food handlers, there is a need for educational programs on proper hygiene habits, modes of transmission and prevention of the infection.

Molecular Identification, Pathogenesis, and Life Cycle of Sarcocystis cruzi from Cattle (Bos taurus) in New Valley Governorate, Egypt

Sarcocystis cruzi was identified by molecular methods from an intermediate host, cattle (Bos taurus), in El-Kharga, New Valley Governorate, Egypt, and its life cycle and pathogenicity were studied in the final host, dogs (Canis familiaris). 600 slaughtered cattle aged 6-8 years (480/120 males/females) were included. In addition, three laboratory-bred, coccidian-free puppies aged 2-3 months were fed infected bovine muscles to locate the definitive host and analyze sporogony. 18S rRNA-specific gene primers were used for DNA amplification from esophageal muscles. These polymerase chain reaction (PCR) amplicons were subjected to restriction fragment length polymorphism (RFLP) and molecular sequence analysis. Infection was detected in 78.8% (473/600; 95% CI, 75.56-82.11%). Histopathological examination of esophageal muscles showed oval- to spherical-shaped cysts, 96.7 μm wide by 326.9 μm long; cysts in cardiac muscles were ovoid and smaller. Infected puppies began shedding sporocysts in feces 7 days post-inoculation and showed distorted organ architecture, severe cellular damage, and inflammatory lesions in liver, kidney, esophagus, and stomach. Three oocysts with different shapes and sizes were identified. Partial 18S rRNA gene sequences of isolated New Valley sarcocysts were identical to S. cruzi isolated from different areas, verifying their genetic relatedness. Our analysis suggests that S. cruzi is the most prevalent in slaughtered cattle in New Valley Governorate, Egypt.

Novel pyrrolopyrimidine derivatives: design, synthesis, molecular docking, molecular simulations and biological evaluations as antioxidant and anti-inflammatory agents

Current medical approaches to control the Covid-19 pandemic are either to directly target the SARS-CoV-2 via innovate a defined drug and a safe vaccine or indirectly target the medical complications of the virus. One of the indirect strategies for fighting this virus has been mainly dependent on using anti-inflammatory drugs to control cytokines storm responsible for severe health complications. We revealed the discovery of novel fused pyrrolopyrimidine derivatives as promising antioxidant and anti-inflammatory agents. The newly synthesised compounds were evaluated for their in vitro anti-inflammatory activity using RAW264.7 cells after stimulation with lipopolysaccharides (LPS). The results revealed that 3a, 4b, and 8e were the most potent analogues. Molecular docking and simulations of these compounds against COX-2, TLR-2 and TLR-4 respectively was performed. The former results were in line with the biological data and proved that 3a, 4b and 8e have potential antioxidant and anti-inflammatory effects.

dynamAedes: a unified modelling framework for invasive Aedes mosquitoes

Mosquito species belonging to the genus Aedes have attracted the interest of scientists and public health officers because of their capacity to transmit viruses that affect humans. Some of these species were brought outside their native range by means of trade and tourism and then colonised new regions thanks to a unique combination of eco-physiological traits. Considering mosquito physiological and behavioural traits to understand and predict their population dynamics is thus a crucial step in developing strategies to mitigate the local densities of invasive Aedes populations. Here, we synthesised the life cycle of four invasive Aedes species (Ae. aegypti, Ae. albopictus, Ae. japonicus and Ae. koreicus) in a single multi-scale stochastic modelling framework which we coded in the R package dynamAedes. We designed a stage-based and time-discrete stochastic model driven by temperature, photo-period and inter-specific larval competition that can be applied to three different spatial scales: punctual, local and regional. These spatial scales consider different degrees of spatial complexity and data availability by accounting for both active and passive dispersal of mosquito species as well as for the heterogeneity of the input temperature data. Our overarching aim was to provide a flexible, open-source and user-friendly tool rooted in the most updated knowledge on the species' biology which could be applied to the management of invasive Aedes populations as well as to more theoretical ecological inquiries.

Escalating pyrethroid resistance in two major malaria vectors Anopheles funestus and Anopheles gambiae (s.l.) in Atatam, Southern Ghana

BACKGROUND

Aggravation of insecticide resistance in malaria vectors is threatening the efforts to control malaria by reducing the efficacy of insecticide-based interventions hence needs to be closely monitored. This study investigated the intensity of insecticide resistance of two major malaria vectors An. funestus sensu stricto (s.s.) and An. gambiae sensu lato (s.l.) collected in southern Ghana and assessed the bio-efficacy of several long-lasting insecticidal nets (LLINs) against these mosquito populations.

METHODS

The insecticide susceptibility profiles of Anopheles funestus s.s. and Anopheles gambiae s.l. populations from Obuasi region (Atatam), southern Ghana were characterized and the bio-efficacy of some LLINs was assessed to determine the impact of insecticide resistance on the effectiveness of these tools. Furthermore, molecular markers associated with insecticide resistance in both species were characterized in the F0 and F1 populations using PCR and qPCR methods.

RESULTS

Anopheles funestus s.s. was the predominant species and was resistant to pyrethroids, organochlorine and carbamate insecticides, but fully susceptible to organophosphates. An. gambiae s.l. was resistant to all four insecticide classes. High intensity of resistance to 5 × and 10 × the discriminating concentration (DC) of pyrethroids was observed in both species inducing a considerable loss of efficacy of long-lasting insecticidal nets (LLINs). Temporal expression analysis revealed a massive 12-fold increase in expression of the CYP6P4a cytochrome P450 gene in An. funestus s.s., initially from a fold change of 41 (2014) to 500 (2021). For both species, the expression of candidate genes did not vary according to discriminating doses. An. gambiae s.l. exhibited high frequencies of target-site resistance including Vgsc-1014F (90%) and Ace-1 (50%) while these mutations were absent in An. funestus s.s.

CONCLUSIONS

The multiple and high intensity of resistance observed in both malaria vectors highlights the need to implement resistance management strategies and the introduction of new insecticide chemistries.

Parasitic strongyle nemabiome communities in wild ruminants in Sweden

Background

Wildlife hosts may serve as reservoirs for strongyles, which can be transmitted to domestic livestock. Therefore, studies evaluating nemabiome compositions in wildlife ruminants are of great use in assessing the possibility of transmission of important nematode pathogens to domestic sheep in Sweden.

Methods

First, fecal samples were collected from roe deer (n = 125), fallow deer (n = 106), red deer (n = 18) and mouflon (n = 13) in south central Sweden during the hunting season in 2019. Second, after fecal examination samples were cultured and the larvae were harvested, followed by DNA extractions. Third, all samples were barcoded and processed for sequence analysis on the PacBio platform. Finally, bioinformatic sequence analysis was conducted with DADA2, while species diversity and richness, as well as interactions between the different hosts, were calculated and analyzed in R.

Results

Nematode ITS2 sequences were found in 225 of 262 (86%) samples. In total, 31 taxa were identified, among which 26 (86%) to the species level. These were found in different combinations, among which 24 (77%) occurred in roe deer, 19 (61%) in fallow deer, 20 (65%) in red deer and 10 (32%) in mouflon. Five of the species found are known to be associated with livestock (Chabertia ovina, Haemonchus contortus, Oesophagostomum venulosum, Teladorsagia circumcincta and Trichostrongylus axei). However, in the present study the relative abundance and prevalence of most of these species were low. The most striking exception was T. axei, which was relatively abundant in all wildlife hosts. Mostly a wide range of wildlife specific nematodes such as Ostertagia leptospicularis and Spiculopteragia spp. were identified including the invasive nematode Spiculopteragia houdemeri, which was found for the first time in red deer, fallow deer, and mouflon in Sweden. The difference in the number of shared species between mouflon and all cervids (n = 6) was less than among all three cervids (n = 8).

Conclusion

In this study, we investigated the community structure of parasitic intestinal nematodes in four wildlife hosts, and we found that the majority of the parasite species identified were wildlife specific. We also found a new, potentially invasive species not reported before. After comparing the nemabiome of the wildlife hosts in this study with a previous study in sheep from the same geographical region, we conclude that the horizontal transmission potential appears to be relatively low. Still, cross-infections of nematodes between game and sheep cannot be completely ignored.

Graphical Abstract

Environmental Contamination of Different Areas of Isfahan Province of Iran with Toxocara spp. Eggs using Molecular Methods

Background

Toxocariasis is a parasitic disease caused by the larval stage of Toxocara canis and Toxocara cati. Infective stage of this parasite for human develops on soil. So, in this work contamination of the soil of public environments in five geographical areas of Isfahan province of Iran has been investigated.

Materials and Methods

In this descriptive study, 355 soil samples were collected from parks, children's playgrounds, student dormitories, and university environments, and examined by Flotation method. The samples were then inspected using microscopic and molecular methods.

Results

From the 355 examined soil samples in 77 (21.69%), and 87 (24.50%) cases Toxocara eggs were detected by microscopic and molecular methods, respectively. In the molecular method, 31 (8.70%) cases of T. cati and 44 (12.39%) cases of T. canis were identified.

Conclusion

Toxocara eggs were identified in all areas of Isfahan province, although contamination rate was higher in Fereydun Shahr and Semirum counties.

Spatiotemporal mapping of malaria incidence in Sudan using routine surveillance data

Malaria is a serious threat to global health, with over \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$95\%$$\end{document}95% of the cases reported in 2020 by the World Health Organization in African countries, including Sudan. Sudan is a low-income country with a limited healthcare system and a substantial burden of malaria. The epidemiology of malaria in Sudan is rapidly changing due to factors including the rapidly developing resistance to drugs and insecticides among the parasites and vectors, respectively; the growing population living in humanitarian settings due to political instability; and the recent emergence of Anopheles stephensi in the country. These factors contribute to changes in the distribution of the parasites species as well as malaria vectors in Sudan, and the shifting patterns of malaria epidemiology underscore the need for investment in improved situational awareness, early preparedness, and a national prevention and control strategy that is updated, evidence based, and proactive. A key component of this strategy is accurate, high-resolution endemicity maps of species-specific malaria. Here, we present a spatiotemporal Bayesian model, developed in collaboration with the Sudanese Ministry of Health, that predicts a fine-scale (1 km \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times $$\end{document}× 1 km) clinical incidence and seasonality profiles for Plasmodium falciparum and Plasmodium vivax across the country. We use monthly malaria case counts for both species collected via routine surveillance between January 2017 and December 2019, as well as a suite of high-resolution environmental covariates to inform our predictions. These epidemiological maps provide a useful resource for strategic planning and cost-effective implementation of malaria interventions, thus informing policymakers in Sudan to achieve success in malaria control and elimination.

Experimental infections of sand flies and geckos with Leishmania (Sauroleishmania) adleri and Leishmania (S.) hoogstraali

Background

Species belonging to the subgenus Sauroleishmania are parasites of reptiles, and traditionally considered to be non-pathogenic to mammals. Knowledge of the development of these parasites in sand flies and their mechanism of transmission is currently lacking. The main aim of this study was to test the susceptibility of various sand fly species to infection by two Sauroleishmania species, focusing on the localization of parasites in the sand fly intestinal tract.

Methods

The development of Leishmania (Sauroleishmania [S.]) adleri and Leishmania (S.) hoogstraali was studied in six sand fly species (Phlebotomus orientalis, P. argentipes, P. sergenti, P. papatasi, P. duboscqi, Sergentomyia schwetzi). Sand flies were fed through a chick-skin membrane on blood containing Sauroleishmania promastigotes, and they were dissected at various time intervals post blood meal (PBM). Guts were examined microscopically for the presence of parasites, and the intensity and localizations of infections were recorded. Morphological forms of both Sauroleishmania species developing in P. orientalis were analyzed. Experimental infections of geckos using sand fly-derived promastigotes were also performed, and the reptiles were repeatedly examined for Sauroleishmania infection by xenodiagnosis and PCR analysis.

Results

High infection rates for both Sauroleishmania species were observed in P. orientalis and P. argentipes, with the parasites migrating anteriorly and undergoing a peripylarian type of development, including colonization of the stomodeal valve. Conversely, the development of L. (S.) adleri in P. sergenti, P. papatasi and Se. schwetzi was restricted to the sand fly hindgut (hypopylarian type of development). Five morphological forms were distinguished for both Sauroleishmania species developing in P. orientalis. All experimentally infected geckos scored negative for Sauroleishmania based on xenodiagnosis and molecular analysis.

Conclusions

The results showed that Sauroleishmania promastigotes can undergo either a peripylarian or hypopylarian type of development in the sand fly intestinal tract, depending on the sand fly species infected. We demonstrated that P. argentipes and P. orientalis, two sand fly species known as permissive vectors for mammalian parasites of subgenus Leishmania, are also highly susceptible to Sauroleishmania as the parasites developed mature late-stage infections, including colonization of the sand fly stomodeal valve. Thus, the role of Phlebotomus sand flies in transmission of Sauroleishmania should be reconsidered and further investigated.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05417-1.

Geographic distribution of the V1016G knockdown resistance mutation in Aedes albopictus: a warning bell for Europe

BACKGROUND

Colonization of large part of Europe by the Asian tiger mosquito Aedes albopictus is causing autochthonous transmission of chikungunya and dengue exotic arboviruses. While pyrethroids are recommended only to reduce/limit transmission, they are widely implemented to reduce biting nuisance and to control agricultural pests, increasing the risk of insurgence of resistance mechanisms. Worryingly, pyrethroid resistance (with mortality < 70%) was recently reported in Ae. albopictus populations from Italy and Spain and associated with the V1016G point mutation in the voltage-sensitive sodium channel gene conferring knockdown resistance (kdr). Genotyping pyrethroid resistance-associated kdr mutations in field mosquito samples represents a powerful approach to detect early signs of resistance without the need for carrying out phenotypic bioassays which require availability of live mosquitoes, dedicated facilities and appropriate expertise.

METHODS

Here we report results on the PCR-genotyping of the V1016G mutation in 2530 Ae. albopictus specimens from 69 sampling sites in 19 European countries.

RESULTS

The mutation was identified in 12 sites from nine countries (with allele frequencies ranging from 1 to 8%), mostly distributed in two geographical clusters. The western cluster includes Mediterranean coastal sites from Italy, France and Malta as well as single sites from both Spain and Switzerland. The eastern cluster includes sites on both sides of the Black Sea in Bulgaria, Turkey and Georgia as well as one site from Romania. These results are consistent with genomic data showing high connectivity and close genetic relationship among West European populations and a major barrier to gene flow between West European and Balkan populations.

CONCLUSIONS

The results of this first effort to map kdr mutations in Ae. albopictus on a continental scale show a widespread presence of the V1016G allele in Europe, although at lower frequencies than those previously reported from Italy. This represents a wake-up call for mosquito surveillance programs in Europe to include PCR-genotyping of pyrethroid resistance alleles, as well as phenotypic resistance assessments, in their routine activities.

Exposure of Anopheles gambiae larvae to a sub-lethal dose of an agrochemical mixture induces tolerance to adulticides used in vector control management

The heavy use of pesticides in agricultural areas often leads to the contamination of nearby mosquito larvae breeding sites. Exposure to complex mixtures of agrochemicals can affect the insecticide sensitivity of mosquito larvae. Our study objective was to determine whether agrochemical residues in Anopheline larval breeding sites can affect the tolerance of adults to commonly used adulticides. We focussed on Fludora® Fusion, a vector control insecticide formulation combining two insecticides (deltamethrin and clothianidin) with different modes of action. An. gambiae larvae were exposed to a sub-lethal dose of a mixture of agrochemical pesticides used in a highly active agricultural area on the Ivory Coast. Comparative bioassays with Fludora Fusion mixture and its two insecticide components (deltamethrin and clothianidin) were carried out between adult mosquitoes exposed or not to the agrochemicals at the larval stage. A transcriptomic analysis using RNA sequencing was then performed on larvae and adults to study the molecular mechanisms underlying the phenotypic changes observed. Bioassays revealed a significantly increased tolerance of adult females to clothianidin (2.5-fold) and Fludora Fusion mixture (2.2-fold) following larval exposure to agrochemicals. Significantly increased tolerance to deltamethrin was not observed suggesting that insecticide exposure affects the adult efficacy of the Fludora Fusion mixture mainly through mechanisms acting on clothianidin. Transcriptomic analysis revealed the potential of agrochemicals to induce various resistance mechanisms including cuticle proteins, detoxification action and altered insecticide sequestration. These results suggest that although the Fludora Fusion mixture is effective for adult vector control, its efficacy may be locally affected by the ecological context. The present study also suggests that, although the complex interactions between the use of agrochemicals and vector control insecticides are difficult to decipher in the field, they still must be considered in the context of insecticide resistance management programmes.

Anopheles stephensi in Africa requires a more integrated response

There are increasing reports of the Asian malaria mosquito, Anopheles stephensi invading and spreading in Eastern Africa. We discuss the importance of these invasions in the context of broader challenges facing malaria control in Africa and argue against addressing it as an isolated problem. Anopheles stephensi is only one of multiple biological threats facing malaria control in the region—and is itself an indication of wide-ranging weaknesses in vector surveillance and control programs. Expanded investigations are needed in both urban and rural areas, especially in countries serviced by the Indian Ocean trade routes, to establish the full extent and future trajectories of the problem. More importantly, instead of tackling this vector species as a stand-alone threat, affected countries should adopt more integrated and multi-sectorial initiatives that can sustainably drive and keep out malaria.

Meteorological and climatic variables predict the phenology of Ixodes ricinus nymph activity in France, accounting for habitat heterogeneity

Ixodes ricinus ticks (Acari: Ixodidae) are the most important vector for Lyme borreliosis in Europe. As climate change might affect their distributions and activities, this study aimed to determine the effects of environmental factors, i.e., meteorological, bioclimatic, and habitat characteristics on host-seeking (questing) activity of I. ricinus nymphs, an important stage in disease transmissions, across diverse climatic types in France over 8 years. Questing activity was observed using a repeated removal sampling with a cloth-dragging technique in 11 sampling sites from 7 tick observatories from 2014 to 2021 at approximately 1-month intervals, involving 631 sampling campaigns. Three phenological patterns were observed, potentially following a climatic gradient. The mixed-effects negative binomial regression revealed that observed nymph counts were driven by different interval-average meteorological variables, including 1-month moving average temperature, previous 3-to-6-month moving average temperature, and 6-month moving average minimum relative humidity. The interaction effects indicated that the phenology in colder climates peaked differently from that of warmer climates. Also, land cover characteristics that support the highest baseline abundance were moderate forest fragmentation with transition borders with agricultural areas. Finally, our model could potentially be used to predict seasonal human-tick exposure risks in France that could contribute to mitigating Lyme borreliosis risk.

Large-herbivore nemabiomes: patterns of parasite diversity and sharing

Amidst global shifts in the distribution and abundance of wildlife and livestock, we have only a rudimentary understanding of ungulate parasite communities and parasite-sharing patterns. We used qPCR and DNA metabarcoding of fecal samples to characterize gastrointestinal nematode (Strongylida) community composition and sharing among 17 sympatric species of wild and domestic large mammalian herbivore in central Kenya. We tested a suite of hypothesis-driven predictions about the role of host traits and phylogenetic relatedness in describing parasite infections. Host species identity explained 27-53% of individual variation in parasite prevalence, richness, community composition and phylogenetic diversity. Host and parasite phylogenies were congruent, host gut morphology predicted parasite community composition and prevalence, and hosts with low evolutionary distinctiveness were centrally positioned in the parasite-sharing network. We found no evidence that host body size, social-group size or feeding height were correlated with parasite composition. Our results highlight the interwoven evolutionary and ecological histories of large herbivores and their gastrointestinal nematodes and suggest that host identity, phylogeny and gut architecture-a phylogenetically conserved trait related to parasite habitat-are the overriding influences on parasite communities. These findings have implications for wildlife management and conservation as wild herbivores are increasingly replaced by livestock.

Leaving no one behind: targeting mobile and migrant populations with health interventions for disease elimination-a descriptive systematic review

BACKGROUND

Mobile and migrant populations (MMPs) pose a unique challenge to disease elimination campaigns as they are often hard to survey and reach with treatment. While some elimination efforts have had success reaching MMPs, other campaigns are struggling to do so, which may be affecting progress towards disease control and elimination. Therefore, this paper reviews the literature on elimination campaigns targeting MMPs across a selection of elimination diseases-neglected tropical diseases, malaria, trypanosomiasis, polio, smallpox, and rinderpest.

METHODS

Through a systematic review process following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a three-person review team identified papers from databases, conference records, and citation searches using inclusion/exclusion criteria. Papers were divided into three key outcome domains during the synthetization process: (1) MMP movement patterns in East Africa including reasons for movement and consequences in terms of health outcomes and healthcare access; (2) MMP contribution to the transmission of disease across all geographies; (3) surveillance methods and treatment interventions used to implement programming in MMPs across all geographies. Experts in the field also provided supplemental information and gray literature to support this review.

RESULTS

The review identified 103 records which were descriptively analyzed using the outcome domains. The results indicate that in East Africa, there are various motivations for migration from economic opportunity to political unrest to natural disasters. Regardless of motivation, mobile lifestyles affect health service access such that MMPs in East Africa report barriers in accessing healthcare and have limited health knowledge. Often lower service delivery to these populations has resulted in higher disease prevalence. A minority of articles suggest MMPs do not pose challenges to reaching disease control and elimination thresholds. Finally, the literature highlighted surveillance methods (e.g., using satellite imagery or mobile phone data to track movement, participatory mapping, snowball sampling) and intervention strategies (e.g., integration with animal health campaigns, cross-border coordination, alternative mass drug administration [MDA] methods) to implement health interventions in MMPs.

CONCLUSIONS

Ultimately, the literature reviewed here can inform programmatic decisions as the community attempts to reach these never treated populations.

SYSTEMATIC REVIEW REGISTRATION

The protocol for this manuscript was registered with the International Prospective Registry of Systematic Reviews (PROSPERO) (No. CRD42021214743).

Molecular epidemiology and genetic characterization of Theileria orientalis in cattle

Theileria orientalis (T. orientalis) is a benign species of Theileria that is found all throughout the world, including Egypt. The purpose of this work was to determine the current status of T. orientalis infection in cattle, as well as to define T. orientalis genetic diversity using the major piroplasm surface protein (MPSP) genes. In 2020, blood samples from 500 asymptomatic cattle were collected, which live in four different governorates at northern Egypt and examined using PCR assay based on MPSP gene. Overall, 44 blood samples (8.8%, 44/500) were positive for T. orientalis, and the highest prevalence rate was observed in Kafer ElSheikh while it was relatively low in Gharbia governorate. Moreover, based on multivariable analysis, the risk of infection with T. orientalis infection was higher in mixed breed cattle and in animals of age group more than 3 years compared to other. Additionally, absence of acaricide application, infestation with ticks, and communal grazing system were identified as potential risk factors for T. orientalis infection. Phylogenetic analysis revealed that the isolates studied belonged to two MPSP genotypes, types 1 and 2. These findings reveal that the MPSP genotypes discovered in the present work displayed genetic variation that was linked to geographic area. Therefore, further research should be focused on developing an effective T. orientalis monitoring and preventive program.

Transcriptomic profiling of Trypanosoma congolense mouthpart parasites from naturally infected flies

Background

Animal African trypanosomiasis, or nagana, is a veterinary disease caused by African trypanosomes transmitted by tsetse flies. In Africa, Trypanosoma congolense is one of the most pathogenic and prevalent causes of nagana in livestock, resulting in high animal morbidity and mortality and extensive production losses. In the tsetse fly, parasites colonise the midgut and eventually reach the mouthparts, from where they can be transmitted as the fly feeds on vertebrate hosts such as cattle. Despite the extreme importance of mouthpart-form parasites for disease transmission, very few global expression profile studies have been conducted in these parasite forms.

Methods

Here, we collected tsetse flies from the Shimba Hills National Reserve, a wildlife area in southeast Kenya, diagnosed T. congolense infections, and sequenced the transcriptomes of the T. congolense parasites colonising the mouthparts of the flies.

Results

We found little correlation between mouthpart parasites from natural and experimental fly infections. Furthermore, we performed differential gene expression analysis between mouthpart and bloodstream parasite forms and identified several surface-expressed genes and 152 novel hypothetical proteins differentially expressed in mouthpart parasites. Finally, we profiled variant antigen expression and observed that a variant surface glycoprotein (VSG) transcript belonging to T. congolense phylotype 8 (i.e. TcIL3000.A.H_000381200), previously observed to be enriched in metacyclic transcriptomes, was present in all wild-caught mouthpart samples as well as bloodstream-form parasites, suggestive of constitutive expression.

Conclusion

Our study provides transcriptomes of trypanosome parasites from naturally infected tsetse flies and suggests that a phylotype 8 VSG gene is constitutively expressed in metacyclic- and bloodstream-form parasites at the population level.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05258-y.

Molecular survey and phylogenetic analysis of Babesia vogeli in dogs

Canine babesiosis is a life-threatening haemoparasitic disease in dogs that is prevalent worldwide. In this study, the prevalence of Babesia vogeli (B. vogeli) was investigated in dogs from Egypt by using Polymerase Chain Reaction (PCR) assay, and associated risk factors were evaluated. In addition, phylogenetic position of B. vogeli Egyptian isolate was determined by sequencing. A total of 275 blood samples were taken from dogs located in four governorates belonging to the north of Egypt. Samples were examined by PCR targeting the B. vogeli 18S rRNA gene and this species was also confirmed by sequencing. Overall, the prevalence of B. vogeli was 5.1% among the studied dogs and the highest prevalence rate was found in the Giza governorate. Univariate logistic regression was used to evaluate each variable individually. The results revealed a significant association between the prevalence of B. vogeli infection and whether or not dogs were infested with ticks and the type of floor used in dog shelters. Additionally, tick infestation (OR 6.1, 95% CI 1.2-31.4), and living in shelters with soil floors (OR 3.8, 95% CI 0.8-17.8) were identified as potential risk factors for B. vogeli infection. Phylogenetic analysis was performed using B. vogeli 18S rRNA partial sequences with the hypervariable V4 region from GenBank. The Egyptian isolate was assigned to second sub-cluster with B. vogeli isolates from Japan, Venezuela and Paraguay within the B. vogeli/B. canis cluster. The present data will be useful to improve the understanding of canine babesiosis epidemiology and ways to control the disease in companion dogs.

The distribution of Dermacentor reticulatus in the Czech Republic re-assessed: citizen science approach to understanding the current distribution of the Babesia canis vector

Background

The range of the ornate dog tick Dermacentorreticulatus is rapidly expanding in Europe. This tick species is the vector of canine babesiosis, caused by Babesiacanis, and also plays a role in the transmission of Theileriaequi and Babesiacaballi in equids.

Methods

The geographic range of D.reticulatus in the Czech Republic was re-assessed, and an up-to-date distribution map is presented based on material and data obtained during a nationwide citizen science campaign. Received and flagged individuals of D.reticulatus were also analysed for the presence of B.canis DNA.

Results

In striking contrast to historical records, D.reticulatus was found in all regions of the Czech Republic, with most reports coming from the southeast and northwest of the country. Between February 2018 and June 2021, the project team received 558 photo reports of ticks and 250 packages containing ticks. Of the former, 71.1% were identified as Dermacentor sp. with the remainder identified as Ixodes sp., Haemaphysalis sp., Argas sp. or Hyalomma sp. The majority of specimens in the subset of ticks that were received (N = 610) were D.reticulatus (N = 568, 93.7%), followed by Ixodesricinus and Hyalomma spp. A total of 783 adult D.reticulatus, either received (568) or collected by flagging (215), were tested for the presence of B.canis DNA using species-specific nested PCR targeting part of the 18S rRNA gene; B.canis DNA was demonstrated in 22 samples (2.81%).

Conclusions

The continuous spread of D.reticulatus in the Czech Republic was documented in this study. In addition, DNA of B.canis was also detected in a number of ticks, suggesting the establishment of B.canis in the Czech Republic. These results suggest that veterinarians need to consider the possibility of canine babesiosis even in dogs without a history of travel.

Graphical Abstract

VectorBase.org updates: bioinformatic resources for invertebrate vectors of human pathogens and related organisms

VectorBase (VectorBase.org) is part of the VEuPathDB Bioinformatics Resource Center, providing free online access to multi-omics and population biology data, focusing on arthropod vectors and invertebrates of importance to human health. VectorBase includes genomics and functional genomics data from bed bugs, biting midges, body lice, kissing bugs, mites, mosquitoes, sand flies, ticks, tsetse flies, stable flies, house flies, fruit flies, and a snail intermediate host. Tools include the Search Strategy system and MapVEu, enabling users to interrogate and visualize diverse 'omics and population-level data using a graphical interface (no programming experience required). Users can also analyze their own private data, such as transcriptomic sequences, exploring their results in the context of other publicly-available information in the database. Help Desk: help@vectorbase.org.

A Practical Insecticide Resistance Monitoring Bioassay for Orally Ingested Dinotefuran in Anopheles Malaria Vectors

Attractive Toxic Sugar Baits (ATSB) deployed outdoors are likely to be particularly effective against outdoor biting mosquitoes and, if they contain insecticides with a different mode of action, mosquitoes resistant to pyrethroids. One such ATSB based on the neonicotinoid dinotefuran is currently under evaluation in Africa. As with any insecticide-based intervention, it will be important to monitor for the possible emergence of vector resistance. While methods for detecting resistance to insecticides via tarsal contact are recommended by the World Health Organization (WHO), these may not be applicable for orally ingested insecticides. Here, a new ingestion assay, appropriate for a controlled laboratory setting, is described using fluorescein sodium salt (uranine) as a feeding marker. Conventional topical application bioassays, more appropriate for routine deployment, have also been used to apply dinotefuran to the thorax of adult Anopheles mosquitoes with an organic carrier to bypass lipid cuticle barriers. The two methods were compared by establishing lethal doses (LD) in several Anopheles strains. The similarity of the ratios of susceptibility to dinotefuran between pairs of pyrethroid susceptible and resistant strains validates topical application as a suitable, more practical and field applicable method for monitoring for the emergence of resistance to orally ingested dinotefuran. A discriminating dose is proposed, which will be further validated against field populations and used to routinely monitor for the emergence of resistance alongside ATSB trials.

Candidate vectors of horizontal transfer of BovB retrotransposon

The horizontal transfer of retrotransposons has a significant impact on the regulatory system of a multicellular organism, but the biological basis of horizontal transfer has been sufficiently studied up to date. Earlier, we identified the conserved sequence of retrotransposons recombination products of the bovine chromosome 1 nucleotide sequence region. This conserved sequence has a high percent identity with LINE BovB, which is widely known as horizontal transfer participant. The current study analyzes the presence of the conserved sequence of retrotransposons recombination products of cattle in members of different taxonomic groups to detect potential vectors of horizontal transfer. It was shown that the conserved sequence with a high percent identity can be found in 43 members of different species, including eukaryotes, prokaryotes and viruses. The identified potential vectors of horizontal retrotransposon transfer associated with various diseases of farm animals are of particular interest. Such potential vectors are hemiparasites Babesia ovata and Babesia bigemina (pathogens causing babesiosis), bacterium Clostridium botulinum (the causative agent of botulism), Jaagsiekte sheep retrovirus (the causative agent of lung cancer in sheep). They all have regions with a high percent identity (not lower than 95%) to the studied bovine conserved sequence. Thus, we identify new potential vectors of horizontal retrotransposon transfer as well as the possible influence of retrotransposons on regulatory networks affecting host protection from infectious diseases.

Concurrent dengue infections: Epidemiology & clinical implications

Multiple dengue virus (DENV) serotypes circulating in a geographical area most often lead to simultaneous infection of two or more serotypes in a single individual. The occurrence of such concurrent infections ranges from 2.5 to 30 per cent, reaching as high as 40-50 per cent in certain dengue hyper-endemic areas. Concurrent dengue manifests itself differently than mono-infected patients, and it becomes even more important to understand the effects of co-infecting serotypes in concurrent infections to ascertain the clinical outcomes of the disease progression and transmission. In addition, there have also been reports of concurrent DENV infections in the presence of other arboviral infections. In this review, we provide a comprehensive breakdown of concurrent dengue infections globally. Furthermore, this review also touches upon the clinical presentations during those concurrent infections categorized as mild or severe forms of disease presentation. Another aspect of this review was aimed at providing insight into the concurrent dengue incidences in the presence of other arboviruses.

Ecological plasticity to ions concentration determines genetic response and dominance of Anopheles coluzzii larvae in urban coastal habitats of Central Africa

In Central Africa, the malaria vector Anopheles coluzzii is predominant in urban and coastal habitats. However, little is known about the environmental factors that may be involved in this process. Here, we performed an analysis of 28 physicochemical characteristics of 59 breeding sites across 5 urban and rural sites in coastal areas of Central Africa. We then modelled the relative frequency of An. coluzzii larvae to these physicochemical parameters in order to investigate environmental patterns. Then, we assessed the expression variation of 10 candidate genes in An. coluzzii, previously incriminated with insecticide resistance and osmoregulation in urban settings. Our results confirmed the ecological plasticity of An. coluzzii larvae to breed in a large range of aquatic conditions and its predominance in breeding sites rich in ions. Gene expression patterns were comparable between urban and rural habitats, suggesting a broad response to ions concentrations of whatever origin. Altogether, An. coluzzii exhibits a plastic response to occupy both coastal and urban habitats. This entails important consequences for malaria control in the context of the rapid urban expansion in Africa in the coming years.

Improvement of water quality for mass anopheline rearing: evaluation of the impact of ammonia-capturing zeolite on larval development and adult phenotypic quality

Background

Malaria vector control approaches that rely on mosquito releases such as the sterile insect technique (SIT) and suppression or replacement strategies relying on genetically modified mosquitoes (GMM) depend on effective mass production of Anopheles mosquitoes. Anophelines typically require relatively clean larval rearing water, and water management techniques that minimise toxic ammonia are key to achieving optimal rearing conditions in small and large rearing facilities. Zeolites are extensively used in closed-system fish aquaculture to improve water quality and reduce water consumption, thanks to their selective adsorption of ammonia and toxic heavy metals. The many advantages of zeolites include low cost, abundance in many parts of the world and environmental friendliness. However, so far, their potential benefit for mosquito rearing has not been evaluated.

Methods

This study evaluated the independent effects of zeolite and daily water changes (to simulate a continuous flow system) on the rearing of An. coluzzii under two feed regimes (powder and slurry feed) and larval densities (200 and 400 larvae per tray). The duration of larval development, adult emergence success and phenotypic quality (body size) were recorded to assess the impact of water treatments on mosquito numbers, phenotypic quality and identification of optimal feeding regimes and larval density for the use of zeolite.

Results

Overall, mosquito emergence, duration of development and adult phenotypic quality were significantly better in treatments with daily water changes. In treatments without daily water changes, zeolite significantly improved water quality at the lower larval rearing density, resulting in higher mosquito emergence and shorter development time. At the lower larval rearing density, the adult phenotypic quality did not significantly differ between zeolite treatment without water changes and those with daily changes.

Conclusions

These results suggest that treating rearing water with zeolite can improve mosquito production in smaller facilities. Zeolite could also offer cost-effective and environmentally friendly solutions for water recycling management systems in larger production facilities. Further studies are needed to optimise and assess the costs and benefits of such applications to Anopheles gambiae (s.l.) mosquito-rearing programmes.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-04763-w.