Prevalence of Plasmodium parasites in non-human primates and mosquitoes in areas with different degrees of fragmentation in Colombia

Overview of Plasmodium spp. and Animal Models in Malaria Research

Malaria is a parasitic disease caused by protozoan species of the genus Plasmodium and transmitted by female mosquitos of the genus Anopheles and other Culicidae. Most of the parasites of the genus Plasmodium are highly species specific with more than 200 species described affecting different species of mammals, birds, and reptiles. Plasmodium species strictly affecting humans are P. falciparum, P. vivax, P. ovale, and P. malariae. More recently, P. knowlesi and other nonhuman primate plasmodia were found to naturally infect humans. Currently, malaria occurs mostly in poor tropical and subtropical areas of the world, and in many of these countries it is the leading cause of illness and death. For more than 100 y, animal models, have played a major role in our understanding of malaria biology. Avian Plasmodium species were the first to be used as models to study human malaria. Malaria parasite biology and immunity were first studied using mainly P. gallinaceum and P. relictum. Rodent malarias, particularly P. berghei and P. yoelii, have been used extensively as models to study malaria in mammals. Several species of Plasmodium from nonhuman primates have been used as surrogate models to study human malaria immunology, pathogenesis, candidate vaccines, and treatments. Plasmodium cynomolgi, P. simiovale, and P. fieldi are important models for studying malaria produced by P. vivax and P. ovale, while P. coatneyi is used as a model for study- ing severe malaria. Other nonhuman primate malarias used in research are P. fragile, P. inui, P. knowlesi, P. simium, and P. brasilianum. Very few nonhuman primate species can develop an infection with human malarias. Macaques in general are resistant to infection with P. falciparum, P. vivax, P. malariae, and P. ovale. Only apes and a few species of New World monkeys can support infection with human malarias. Herein we review the most common, and some less common, avian, reptile, and mammal plasmodia species used as models to study human malaria.

Diversity and prevalence of zoonotic infections at the animal-human interface of primate trafficking in Peru

Wildlife trafficking creates favorable scenarios for intra- and inter-specific interactions that can lead to parasite spread and disease emergence. Among the fauna affected by this activity, primates are relevant due to their potential to acquire and share zoonoses - infections caused by parasites that can spread between humans and other animals. Though it is known that most primate parasites can affect multiple hosts and that many are zoonotic, comparative studies across different contexts for animal-human interactions are scarce. We conducted a multi-parasite screening targeting the detection of zoonotic infections in wild-caught monkeys in nine Peruvian cities across three contexts: captivity (zoos and rescue centers, n = 187); pet (households, n = 69); and trade (trafficked or recently confiscated, n = 132). We detected 32 parasite taxa including mycobacteria, simian foamyvirus, bacteria, helminths, and protozoa. Monkeys in the trade context had the highest prevalence of hemoparasites (including Plasmodium malariae/brasilianum, Trypanosoma cruzi, and microfilaria) and enteric helminths and protozoa were less common in pet monkeys. However, parasite communities showed overall low variation between the three contexts. Parasite richness (PR) was best explained by host genus and the city where the animal was sampled. Squirrel (genus Saimiri) and wooly (genus Lagothrix) monkeys had the highest PR, which was ~2.2 times the PR found in tufted capuchins (genus Sapajus) and tamarins (genus Saguinus/Leontocebus) in a multivariable model adjusted for context, sex, and age. Our findings illustrate that the threats of wildlife trafficking to One Health encompass exposure to multiple zoonotic parasites well-known to cause disease in humans, monkeys, and other species. We demonstrate these threats continue beyond the markets where wildlife is initially sold; monkeys trafficked for the pet market remain a reservoir for and contribute to the translocation of zoonotic parasites to households and other captive facilities where contact with humans is frequent. Our results have practical applications for the healthcare of rescued monkeys and call for urgent action against wildlife trafficking and ownership of monkeys as pets.

Simian malaria: a narrative review on emergence, epidemiology and threat to global malaria elimination

Simian malaria from wild non-human primate populations is increasingly recognised as a public health threat and is now the main cause of human malaria in Malaysia and some regions of Brazil. In 2022, Malaysia became the first country not to achieve malaria elimination due to zoonotic simian malaria. We review the global distribution and drivers of simian malaria and identify priorities for diagnosis, treatment, surveillance, and control. Environmental change is driving closer interactions between humans and wildlife, with malaria parasites from non-human primates spilling over into human populations and human malaria parasites spilling back into wild non-human primate populations. These complex transmission cycles require new molecular and epidemiological approaches to track parasite spread. Current methods of malaria control are ineffective, with wildlife reservoirs and primarily outdoor-biting mosquito vectors urgently requiring the development of novel control strategies. Without these, simian malaria has the potential to undermine malaria elimination globally.

Environmental and socio-economic determinants of the occurrence of malaria clusters in Colombia

This study identifies the environmental and socio-economic determinants of clusters of high malaria incidence in Colombia during the period of 2008-2019. The malaria cases were obtained from the National System of Surveillance in Public Health, with 798,897 cases reported in the 986 Colombian municipalities evaluated during the study period. Spatial autocorrelation of incidence was examined with global and local indices. Clusters were identified in the Amazon, Pacific, and Uraba-Bajo Cauca-Alto Sinú regions. The factors associated with a municipality belonging to a high-incidence cluster were identified using a logistic regression model with mixed effects and showed a positive association for the variables (forest coverage and minimum multi-year average rainfall). An inverse relationship was observed for aqueduct coverage and the odds of belonging to a cluster. A 1% increase in forest coverage was associated with a 4.2% increase in the odds of belonging to a malaria cluster. The association with minimum multi-year average rainfall was positive (OR = 1.0011; 95% CI 1.0005-1.0027). A 1% increase in aqueduct coverage was associated with a 4.3% decrease in the odds of belonging to malaria cluster. The identification of malaria cluster determinants in Colombia could help guide surveillance and disease control policies.

Is zoonotic Plasmodium vivax malaria an obstacle for disease elimination?

Background

The groundwork for malaria elimination does not currently consider the potential of Plasmodium zoonotic cycles that involve non-human primates (NHPs) in sylvatic environments. Since vivax malaria is less responsive to control measures, finding Plasmodium vivax infected NHPs adds even more concern.

Methods

Both Free-living monkeys in forest fragments inside the urban area and captive monkeys from a local zoo had blood samples tested for Plasmodium species.

Results

In this study, among the Neotropical monkeys tested, three (4.4%), one captive and two free-living, were found to be naturally infected by P. vivax.

Conclusion

This important finding indicates that it is necessary to estimate the extent to which P. vivax NHP infection contributes to the maintenance of malaria transmission to humans. Therefore, the discussion on wildlife conservation and management must be incorporated into the malaria elimination agenda.

A Follow-Up to the Geographical Distribution of Anopheles Species in Malaria-Endemic and Non-Endemic Areas of Honduras

Simple Summary

Malaria is a tropical disease caused by parasites of the genus Plasmodium. The parasite is transmitted to humans through the bite of the female mosquito Anopheles. Honduras is close to the goal of eliminating malaria, but the region called La Moskitia continues to concentrate almost all of the country’s malaria cases. One of the key factors in achieving malaria elimination is a thorough understanding of the mosquito vectors that transmit the disease. There are few studies related to malaria vectors in Honduras. This study aims to contribute to knowing which are the species of vector mosquitoes, mainly in the Department of Gracias a Dios and in other departments in which cases of malaria occur, in addition to describing molecularly for the first time the anophelines of the Bay Islands. The most abundant species found here were Anopheles albimanus, but seven other species were also identified, some of which may contribute to parasite transmission.

Abstract

Anopheles species are the vectors of malaria, one of the diseases with the greatest impact on the health of the inhabitants of the tropics. Due to their epidemiological relevance and biological complexity, monitoring of anopheline populations in current and former malaria-endemic areas is critical for malaria risk assessment. Recent efforts have described the anopheline species present in the main malaria foci in Honduras. This study updates and expands knowledge about Anopheles species composition, geographical distribution, and genetic diversity in the continental territory of Honduras as in the Bay Islands. Outdoor insect collections were carried out at 25 sites in eight municipalities in five departments of Honduras between 2018 and 2021. Specimens were identified using taxonomic keys. Partial COI gene sequences were used for molecular species identification and phylogenetic analyses. In addition, detection of Plasmodium DNA was carried out in 255 female mosquitoes. Overall, 288 Anopheles mosquitoes were collected from 8 municipalities. Eight species were morphologically identified. Anopheles albimanus was the most abundant and widely distributed species (79.5%). A subset of 175 partial COI gene sequences from 8 species was obtained. Taxonomic identifications were confirmed via sequence analysis. Anopheles albimanus and An. apicimacula showed the highest haplotype diversity and nucleotide variation, respectively. Phylogenetic clustering was found for An. argyritarsis and An. neomaculipalpus when compared with mosquitoes from other Neotropical countries. Plasmodium DNA was not detected in any of the mosquitoes tested. This report builds upon recent records of the distribution and diversity of Anopheles species in malaria-endemic and non-endemic areas of Honduras. New COI sequences are reported for three anopheline species. This is also the first report of COI sequences of An. albimanus collected on the island of Roatán with apparent gene flow relative to mainland populations.

The primate malaria parasites Plasmodium malariae, Plasmodium brasilianum and Plasmodium ovale spp.: genomic insights into distribution, dispersal and host transitions

During the twentieth century, there was an explosion in understanding of the malaria parasites infecting humans and wild primates. This was built on three main data sources: from detailed descriptive morphology, from observational histories of induced infections in captive primates, syphilis patients, prison inmates and volunteers, and from clinical and epidemiological studies in the field. All three were wholly dependent on parasitological information from blood-film microscopy, and The Primate Malarias” by Coatney and colleagues (1971) provides an overview of this knowledge available at that time. Here, 50 years on, a perspective from the third decade of the twenty-first century is presented on two pairs of primate malaria parasite species. Included is a near-exhaustive summary of the recent and current geographical distribution for each of these four species, and of the underlying molecular and genomic evidence for each. The important role of host transitions in the radiation of Plasmodium spp. is discussed, as are any implications for the desired elimination of all malaria species in human populations. Two important questions are posed, requiring further work on these often ignored taxa. Is Plasmodium brasilianum, circulating among wild simian hosts in the Americas, a distinct species from Plasmodium malariae? Can new insights into the genomic differences between Plasmodium ovale curtisi and Plasmodium ovale wallikeri be linked to any important differences in parasite morphology, cell biology or clinical and epidemiological features?

Evolutionary history of Plasmodium vivax and Plasmodium simium in the Americas

Malaria is a vector-borne disease caused by protozoan parasites of the genus Plasmodium. Plasmodium vivax is the most prevalent human-infecting species in the Americas. However, the origins of this parasite in this continent are still debated. Similarly, it is now accepted that the existence of Plasmodium simium is explained by a P. vivax transfer from humans to monkey in America. However, many uncertainties still exist concerning the origin of the transfer and whether several transfers occurred. In this review, the most recent studies that addressed these questions using genetic and genomic approaches are presented.

Primate malarias as a model for cross-species parasite transmission

Parasites regularly switch into new host species, representing a disease burden and conservation risk to the hosts. The distribution of these parasites also gives insight into characteristics of ecological networks and genetic mechanisms of host-parasite interactions. Some parasites are shared across many species, whereas others tend to be restricted to hosts from a single species. Understanding the mechanisms producing this distribution of host specificity can enable more effective interventions and potentially identify genetic targets for vaccines or therapies. As ecological connections between human and local animal populations increase, the risk to human and wildlife health from novel parasites also increases. Which of these parasites will fizzle out and which have the potential to become widespread in humans? We consider the case of primate malarias, caused by Plasmodium parasites, to investigate the interacting ecological and evolutionary mechanisms that put human and nonhuman primates at risk for infection. Plasmodium host switching from nonhuman primates to humans led to ancient introductions of the most common malaria-causing agents in humans today, and new parasite switching is a growing threat, especially in Asia and South America. Based on a wild host-Plasmodium occurrence database, we highlight geographic areas of concern and potential areas to target further sampling. We also discuss methodological developments that will facilitate clinical and field-based interventions to improve human and wildlife health based on this eco-evolutionary perspective.

The bacterial biome of ticks and their wildlife hosts at the urban-wildland interface

Advances in sequencing technologies have revealed the complex and diverse microbial communities present in ticks (Ixodida). As obligate blood-feeding arthropods, ticks are responsible for a number of infectious diseases that can affect humans, livestock, domestic animals and wildlife. While cases of human tick-borne diseases continue to increase in the northern hemisphere, there has been relatively little recognition of zoonotic tick-borne pathogens in Australia. Over the past 5 years, studies using high-throughput sequencing technologies have shown that Australian ticks harbour unique and diverse bacterial communities. In the present study, free-ranging wildlife (n=203), representing ten mammal species, were sampled from urban and peri-urban areas in New South Wales (NSW), Queensland (QLD) and Western Australia (WA). Bacterial metabarcoding targeting the 16S rRNA locus was used to characterize the microbiomes of three sample types collected from wildlife: blood, ticks and tissue samples. Further sequence information was obtained for selected taxa of interest. Six tick species were identified from wildlife: Amblyomma triguttatum, Ixodes antechini, Ixodes australiensis, Ixodes holocyclus, Ixodes tasmani and Ixodes trichosuri. Bacterial 16S rRNA metabarcoding was performed on 536 samples and 65 controls, generating over 100 million sequences. Alpha diversity was significantly different between the three sample types, with tissue samples displaying the highest alpha diversity (P<0.001). Proteobacteria was the most abundant taxon identified across all sample types (37.3 %). Beta diversity analysis and ordination revealed little overlap between the three sample types (P<0.001). Taxa of interest included Anaplasmataceae, Bartonella, Borrelia, Coxiellaceae, Francisella, Midichloria, Mycoplasma and Rickettsia. Anaplasmataceae bacteria were detected in 17.7% (95/536) of samples and included Anaplasma, Ehrlichia and Neoehrlichia species. In samples from NSW, 'Ca. Neoehrlichia australis', 'Ca. Neoehrlichia arcana', Neoehrlichia sp. and Ehrlichia sp. were identified. A putative novel Ehrlichia sp. was identified from WA and Anaplasma platys was identified from QLD. Nine rodent tissue samples were positive for a novel Borrelia sp. that formed a phylogenetically distinct clade separate from the Lyme Borrelia and relapsing fever groups. This novel clade included recently identified rodent-associated Borrelia genotypes, which were described from Spain and North America. Bartonella was identified in 12.9% (69/536) of samples. Over half of these positive samples were obtained from black rats (Rattus rattus), and the dominant bacterial species identified were Bartonella coopersplainsensis and Bartonella queenslandensis. The results from the present study show the value of using unbiased high-throughput sequencing applied to samples collected from wildlife. In addition to understanding the sylvatic cycle of known vector-associated pathogens, surveillance work is important to ensure preparedness for potential zoonotic spillover events.

Parasites of Free-Ranging and Captive American Primates: A Systematic Review

The diversity, spread, and evolution of parasites in non-human primates (NHPs) is a relevant issue for human public health as well as for NHPs conservation. Although previous reviews have recorded information on parasites in NHPs (Platyrrhines) in the Americas, the increasing number of recent studies has made these inventories far from complete. Here, we summarize information about parasites recently reported in Platyrrhines, attempting to build on earlier reviews and identify information gaps. A systematic literature search was conducted in PubMed, ISI Web of Science, and Latin American and Caribbean Health Sciences Literature (LILACS), and following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Ninety-three studies were included after the screening process. Records for 20 genera of NHPs, including 90 species were found. Most of the studies were conducted on captive individuals (54.1%), and morphological approaches were the most used for parasite identification. The most commonly collected biological samples were blood and stool, and Protozoa was the most frequent parasite group found. There is still scarce (if any) information on the parasites associated to several Platyrrhine species, especially for free-ranging populations. The use of molecular identification methods can provide important contributions to the field of NHPs parasitology in the near future. Finally, the identification of parasites in NHPs populations will continue to provide relevant information in the context of pervasive habitat loss and fragmentation that should influence both human public health and wildlife conservation strategies.

A population genetic perspective on the origin, spread and adaptation of the human malaria agents Plasmodium falciparum and Plasmodium vivax

Malaria is considered one of the most important scourges that humanity has faced during its history, being responsible every year for numerous deaths worldwide. The disease is caused by protozoan parasites, among which two species are responsible of the majority of the burden, Plasmodium falciparum and Plasmodium vivax. For these two parasite species, the questions of their origin (how and when they appeared in humans), of their spread throughout the world, as well as how they have adapted to humans have long been of interest to the scientific community. Here, we review the current knowledge that has accumulated on these different questions, thanks in particular to the analysis of the genetic and genomic variability of these parasites and comparison with related Plasmodium species infecting other host species (like non-human primates). In this paper we review the existing body of knowledge, including current research dealing with these questions, focusing particularly on genetic analysis and genomic variability of these parasites and comparison with related Plasmodium species infecting other species of host (such as non-human primates).

Zoonotic Blood-Borne Pathogens in Non-Human Primates in the Neotropical Region: A Systematic Review

Background: Understanding which non-human primates (NHPs) act as a wild reservoir for blood-borne pathogens will allow us to better understand the ecology of diseases and the role of NHPs in the emergence of human diseases in Ecuador, a small country in South America that lacks information on most of these pathogens. Methods and principal findings: A systematic review was carried out using PRISMA guidelines from 1927 until 2019 about blood-borne pathogens present in NHPs of the Neotropical region (i.e., South America and Middle America). Results: A total of 127 publications were found in several databases. We found in 25 genera (132 species) of NHPs a total of 56 blood-borne pathogens in 197 records where Protozoa has the highest number of records in neotropical NHPs (n = 128) compared to bacteria (n = 12) and viruses (n = 57). Plasmodium brasilianum and Trypanosoma cruzi are the most recorded protozoa in NHP. The neotropical primate genus with the highest number of blood-borne pathogens recorded is Alouatta sp. (n = 32). The use of non-invasive samples for neotropical NHPs remains poor in a group where several species are endangered or threatened. A combination of serological and molecular techniques is common when detecting blood-borne pathogens. Socioecological and ecological risk factors facilitate the transmission of these parasites. Finally, a large number of countries remain unsurveyed, such as Ecuador, which can be of public health importance. Conclusions and significance: NHPs are potential reservoirs of a large number of blood-borne pathogens. In Ecuador, research activities should be focused on bacteria and viruses, where there is a gap of information for neotropical NHPs, in order to implement surveillance programs with regular and effective monitoring protocols adapted to NHPs.

Highly sensitive droplet digital PCR-based diagnostics for the surveillance of malaria vector populations in low transmission and incipient resistance settings

BACKGROUND

Sensitive monitoring of Plasmodium infective mosquitoes in low malaria transmission settings is of high priority for disease control. Early detection of insecticide resistance at low frequencies is also key for vector monitoring nowadays, when new insecticides are launched to control vector populations.

RESEARCH DESIGN AND METHODS

An. gambiae mosquitoes with predetermined infection and resistance status were used to produce populations with various malaria infection rates and mutant allelic frequencies (MAFs) of target site insecticide resistance traits. Total RNA and gDNA were isolated and used in droplet Digital PCR (ddPCR) and Reverse Transcription (RT) ddPCR performed in the QX200 ddPCR System.

RESULTS

We developed a novel ddPCR for detecting P. falciparum DNA in pooled mosquito head-thoraces with infective rate as low as 1.0%. A dissection-free RT-ddPCR assay for specific infective-stage detection was additionally developed and validated (accuracy = 100%) in mosquito pools with infective rates down to 1.0%. A novel ddPCR assay for insecticide resistant alleles, which was able to reliably quantify MAFs as low as 0.050% in pooled mosquito specimens, is also reported.

CONCLUSIONS

We developed highly sensitive and efficient (RT-) ddPCR assays for contemporary operational needs that require monitoring of low malaria transmission and emerging insecticide resistance.

Malaria risk stratification in Colombia 2010 to 2019

Background

Heterogeneity and focalization are the most common epidemiological characteristics of endemic countries in the Americas, where malaria transmission is moderate and low. During malaria elimination, the first step is to perform a risk stratification exercise to prioritize interventions. This study aimed to identify malaria risk strata in the ecoepidemiological regions of Colombia.

Methods

This was a descriptive and retrospective study using cumulative malaria cases in 1,122 municipalities of Colombia from 2010 to 2019. To identify the strata, the criteria proposed by PAHO were adapted. To classify the receptive areas (strata 2, 3, and 4) and nonreceptive areas (stratum 1), 1,600 m above sea level, ecotypes, main malaria vector presence, Plasmodium species prevalence and occurrence of malaria cases were used. The area occupied by the receptive municipalities, the cumulative burden, and the at-risk population in the regions were calculated.

Results

Ninety-one percent of the Colombian territory is receptive to the transmission of malaria and includes 749 municipalities with 9,734,271 (9,514,243–9,954,299) million at-risk inhabitants. Stratum 4 accounted for 96.7% of the malaria burden, and cases were concentrated primarily in the Pacific and Uraba-Bajo Cauca-Sinu-San Jorge regions. Plasmodium vivax predominates in most of the receptive municipalities, except in the municipalities of the Pacific region, where P. falciparum predominates. Anopheles albimanus, An. nuneztovari s.l., and An. darlingi were the main vectors in receptive areas.

Conclusions

In Colombia, 91.2% of the territory is receptive to the transmission of malaria and is characterized by being both heterogeneous and focused. Stratum 4 contains the greatest burden of disease, with a relatively greater proportion of municipalities with a predominance of P. vivax. However, there is a low proportion of municipalities with P. falciparum mainly in the Pacific region. These findings suggest that the latter be prioritized within the malaria elimination plan in Colombia.

Atlantic Forest Malaria: A Review of More than 20 Years of Epidemiological Investigation

In the south and southeast regions of Brazil, cases of malaria occur outside the endemic Amazon region near the Atlantic Forest in some coastal states, where Plasmodium vivax is the recognized parasite. Characteristics of cases and vectors, especially Anopheles (Kerteszia) cruzii, raise the hypothesis of a zoonosis with simians as reservoirs. The present review aims to report on investigations of the disease over a 23-year period. Two main sources have provided epidemiological data: the behavior of Anopheles vectors and the genetic and immunological aspects of Plasmodium spp. obtained from humans, Alouatta simians, and Anopheles spp. mosquitoes. Anopheles (K.) cruzii is the most captured species in the forest canopy and is the recognized vector. The similarity between P. vivax and Plasmodium simium and that between Plasmodium malariae and Plasmodium brasilianum shared between simian and human hosts and the involvement of the same vector in the transmission to both hosts suggest interspecies transfer of the parasites. Finally, recent evidence points to the presence of Plasmodium falciparum in a silent cycle, detected only by molecular methods in asymptomatic individuals and An. (K.) cruzii. In the context of malaria elimination, it is paramount to assemble data about transmission in such non-endemic low-incidence areas.

C, Pacheco MA, Escalante AA, Mureb Sallum MA, Laporta GZ. Complexity of malaria transmission dynamics in the Brazilian Atlantic Forest

Plasmodium malariae and Plasmodium vivax are protozoan parasites that can cause malaria in humans. They are genetically indistinguishable from, respectively, Plasmodium brasilianum and Plasmodium simium, i.e. parasites infecting New World non-human primates in South America. In the tropical rainforests of the Brazilian Atlantic coast, it has long been hypothesized that P. brasilianum and P. simium in platyrrhine primates originated from P. malariae and P. vivax in humans. A recent hypothesis proposed the inclusion of Plasmodium falciparum into the transmission dynamics between humans and non-human primates in the Brazilian Atlantic tropical rainforest. Herein, we assess the occurrence of human malaria in simians and sylvatic anophelines using field-collected samples in the Capivari-Monos Environmental Protection Area from 2015 to 2017. We first tested simian blood and anopheline samples. Two simian (Aloutta) blood samples (18%, n = 11) showed Plasmodium cytb DNA sequences, one for P. vivax and another for P. malariae. From a total of 9,416 anopheline females, we found 17 pools positive for Plasmodium species with a 18S qPCR assay. Only three showed P. cytb DNA sequence, one for P. vivax and the others for rodent malaria species (similar to Plasmodium chabaudi and Plasmodium berghei). Based on these results, we tested 25 rodent liver samples for the presence of Plasmodium and obtained P. falciparum cytb DNA sequence in a rodent (Oligoryzomys sp.) liver. The findings of this study indicate complex malaria transmission dynamics composed by parallel spillover-spillback of human malaria parasites, i.e. P. malariae, P. vivax, and P. falciparum, in the Brazilian Atlantic forest.

•

Human malaria parasites circulate in sylvatic cycles in the Brazilian Atlantic forest.

•

Plasmodium vivax and Plasmodium malariae identified in simian blood samples.

•

Plasmodium falciparum detected in a rodent liver sample.

•

Anopheline vectors found to carry human and rodent malaria parasites.

•

Local vector ecology and biology are key to the spillover-spillback of human malaria parasites.

Detection and characterization of Plasmodium spp. by semi-nested multiplex PCR both in mosquito vectors and in humans residing in historically endemic areas of Paraguay

In Paraguay, no cases of Malaria have been recorded since 2011. Microscopy and the SnM-PCR technique were implemented to detect and characterize Plasmodium spp. both in mosquitoes and in humans residing in historically endemic areas of Paraguay, to evaluate the possibility of finding asymptomatic cases and/or Plasmodium parasites circulating in anophelines. Between 2013 and 2015, 361 human blood samples were collected on filter paper, and between 2016 and 2017, 938 female Anopheles mosquitoes were captured in 15 Paraguayan localities. All the diagnostic techniques showed negative results. We observed no asymptomatic case or Plasmodium circulating in vectors.