Cryptosporidium and Giardia as foodborne zoonoses

A fractional perspective on the transmission dynamics of a parasitic infection, considering the impact of both strong and weak immunity

Infectious disease cryptosporidiosis is caused by the cryptosporidium parasite, a type of parasitic organism. It is spread through the ingestion of contaminated water, food, or fecal matter from infected animals or humans. The control becomes difficult because the parasite may remain in the environment for a long period. In this work, we constructed an epidemic model for the infection of cryptosporidiosis in a fractional framework with strong and weak immunity concepts. In our analysis, we utilize the well-known next-generation matrix technique to evaluate the reproduction number of the recommended model, indicated by [Formula: see text]. As [Formula: see text], our results show that the disease-free steady-state is locally asymptotically stable; in other cases, it becomes unstable. Our emphasis is on the dynamical behavior and the qualitative analysis of cryptosporidiosis. Moreover, the fixed point theorem of Schaefer and Banach has been utilized to investigate the existence and uniqueness of the solution. We identify suitable conditions for the Ulam-Hyers stability of the proposed model of the parasitic infection. The impact of the determinants on the sickness caused by cryptosporidiosis is highlighted by the examination of the solution pathways using a novel numerical technique. Numerical investigation is conducted on the solution pathways of the system while varying various input factors. Policymakers and health officials are informed of the crucial factors pertaining to the infection system to aid in its control.

Prevalence and Genotyping of Water- and Food-Borne Parasitic Protozoans (Giardia duodenalis and Cryptosporidium spp.) in Hospitalized Patients from Northwestern Romania

Giardia duodenalis and Cryptosporidium spp. are important zoonotic protozoan pathogens that infect the gastro-intestinal tract of numerous vertebrates, including humans, and both parasites are responsible for water- or food-borne outbreaks of disease worldwide. Although, globally, both parasites are highly prevalent, particularly in developing countries, epidemiological data from Romania are scarce, and genotyping has rarely been performed. The aims of the present study were to investigate the occurrence and genetic diversity of G. duodenalis and Cryptosporidium spp. in patients hospitalized in Northwestern Romania in relation to clinical and paraclinical presentation and to identify the relative frequency of non-specific symptoms and potential risk factors. Between June 2022 and January 2024, 426 fecal samples were screened for gastro-intestinal parasites by rapid tests and microscopical examination, further confirmed by PCR and sequencing. Giardia duodenalis was detected and characterized in 12 samples (2.82%), while Cryptosporidium parvum was confirmed in four samples (0.94%). A majority of positive patients were symptomatic and reported nausea and vomiting with a significantly higher frequency compared to negative ones. This study provides new insights into the epidemiological status and clinical implications of gastro-intestinal parasite species and genospecies in Romania that are necessary for an in-depth understanding of the potential zoonotic transmission and improvement of patient care.

Functional characterization of phospholipase B enzyme from Giardia lamblia

The microaerotolarent amitochondriate protozoan Giardia lamblia causes Giardiasis and produces a unique enzyme called Phospholipase B (PLB) in contrast to higher eukaryotes. The enzyme is produced upon induction with oxidative (H2O2) stress, thus leading to prostaglandin E2 (PGE2) production. It exists in dimeric form, and its molecular weight is 56 kDa. This PLB was extracellularly cloned in the pET21d vector. The ORF is 1620 bp (Genbank accession no. -OM939681) long and codes for a protein 539 amino acid long, with a 15 amino acid long amino-terminal signal peptide. The highest enzyme activity of PLB was identified at pH 7.5 and 35 °C. This specific enzyme was also active at 50 °C pH 10, but activity was low. We also analyzed the expression of PLB protein in G. lamblia, which was significantly induced under increased oxidative stress.

Genetic diversity and molecular diagnosis of Giardia

Giardia is a genus of flagellated protozoan parasites that infect the small intestine of humans and animals, causing the diarrheal illness known as giardiasis. Giardia exhibits significant genetic diversity among its isolates, which can have important implications for disease transmission and clinical presentation. This diversity is influenced by the coevolution of Giardia with its host, resulting in the development of unique genetic assemblages with distinct phenotypic characteristics. Although panmixia has not been observed, some assemblages appear to have a broader host range and exhibit higher transmission rates. Molecular diagnostic methods enable researchers to examine the genetic diversity of Giardia populations, enhancing our understanding of the genetic diversity, population structure, and transmission patterns of this pathogen and providing insights into clinical presentations of giardiasis.

Molecular Detection and Epidemiology of Potentially Zoonotic Cryptosporidium spp. and Giardia duodenalis in Wild Boar (Sus scrofa) from Eastern Spain

The protozoans Giardia duodenalis and Cryptosporidium spp. are common causes of gastrointestinal disease in humans and animals. While both are commonly documented in domestic animals, few studies have analysed their presence in wildlife. To assess the prevalence of both parasites in wild boar (Sus scrofa) in the Valencian Community (eastern Spain), 498 wild boar faecal samples were collected from 2018 to 2022. Cryptosporidium spp. was detected by performing a nested PCR targeting a 578 bp sequence of the small subunit ribosomal RNA gene (SSU rRNA), followed by sequencing and phylogenetic analysis. For G. duodenalis, a qPCR amplifying a fragment of 62 bp from the SSU rRNA was employed. Positive samples were genotyped for glutamate dehydrogenase and β-giardin genes. Different epidemiological factors were considered potential modulating variables in the transmission of both parasites. G. duodenalis prevalence was 1.20%, while Cryptosporidium spp. prevalence reached 21.7%. Coinfection was observed in 0.2%. Genotyping of G. duodenalis isolates only detected genotype E. Two species of Cryptosporidium spp. were identified: Cryptosporidium scrofarum and Cryptosporidium suis. The results of this study demonstrate that the exposure to Cryptosporidium spp. in wild boars is high, particularly among young individuals belonging to the Typical Mediterranean climate. Moreover, the probability of infection is dependent on both the season and the density of wild boars. On the other side, exposure to G. duodenalis seems scarce and is influenced, in turn, by the climate. Both Cryptosporidium species detected in the present study have been reported in humans. Due to wild boar increasing in number and their colonisation of urban and peri-urban areas, this could represent an inherent health risk for the human population.

Quantitative microbial risk assessment (QMRA) for setting health-based performance targets during soil aquifer treatment

A quantitative microbial risk assessment was conducted to assess the health risks associated with the exposure of agricultural workers to tertiary treated wastewater in irrigated fields through soil ingestion in Cyprus. Three pathogenic microorganisms were chosen, particularly E. coli (bacteria), rotavirus (viruses) and Cryptosporidium. Two extreme exposure scenarios were investigated. Monte Carlo simulations were performed using input data from literature, and the model outputs were compared to the health standards of the World Health Organization (WHO). The results suggested that additional treatment is required for all pathogens to satisfy the health standards. Sensitivity analysis identified the source concentration and pathogen reduction due to soil aquifer passage as the most influential factors in the model outputs. Additional computations were performed to evaluate the minimum pathogen reduction due to soil aquifer passage so that the health targets are achieved for the 95 % of the output values. Rotavirus and Cryptosporidium were found to require more treatment than E. coli. The inclusion of these reference pathogens to the monitoring network of the local authorities is recommended, and the role of soil aquifer passage is emphasized on reducing the concentration of the contaminants.

Prevalence of Cryptosporidium spp. in Horses from communities of the Mapuche native people, Araucanía Region, Chile

BACKGROUND

There are no studies of potential zoonotic diseases in Mapuche communities' horses.

OBJECTIVES

The objective of this study was to determine the prevalence of Cryptosporidium in horses of the Mapuche communities.

STUDY DESIGN

This was a cross-sectional study.

METHODS

Faecal samples from 100 randomly selected horses (n = 100) were taken from rural Mapuche communities from four municipalities from the Araucanía Region. These samples were processed with the modified Ziehl-Neelsen staining technique and grouped by sex, age and municipality.

RESULTS

The general prevalence of Cryptosporidium spp. was 67.0% (n = 67). The prevalence was 51.0% (n = 51) in males and 49.0% (n = 49) in females, and there is no gender association to the presentation of Cryptosporidium spp. The prevalence by municipality was 60.0%, 80.0%, 64.0% and 64.0% in Curarrehue, Lonquimay, Padre las Casas and Teodoro Schmidt, respectively. The above shows no significant association between the sector and the presence of Cryptosporidium spp. The prevalence by age was 95.4% of horses tested positive for Cryptosporidium between birth and 6 years of age. About 27.3% of horses were tested positive in the age group between 7 and 10 years. There was no presence of Cryptosporidium spp. in the age group older than 11 years, showing a significant relationship between the age of the animal and the presence of Cryptosporidium (P ˂ 0.05).

MAIN LIMITATIONS

The sample analysis did not specifically identify the type of Cryptosporidium, and it was not possible to evaluate the zoonotic risk in the Mapuche communities.

CONCLUSIONS

Cryptosporidium spp. is present in working horses in Mapuche communities, with a 67.7% general prevalence, and there is a significant association between this parasite and the age of the horses, being higher in the age group between 0 and 6 years, with a prevalence of 95.4%. There may be a potential zoonotic risk in the Mapuche communities.

Development of duplex real-time PCR for quick detection of cryptosporidiosis in goats

Cryptosporidium spp. is the most important foodborne and waterborne pathogens and a leading cause of mortality from foodborne and waterborne gastrointestinal diseases. In neonates of domestic animals, it is associated with consistent diarrhea and dehydration. Cryptosporidium infection begins with the ingestion of sporulated oocytes disseminated by carrier animals that consistently contaminate the environment. Many diagnostic tests are available including microscopy and antigen trap-ELISA, but none of the diagnostic tests available currently cannot differentiate between active and passive infection in the host. In the current study, to address this challenge an mRNA-based duplex TaqMan® probe PCR was developed to target the Cryptosporidium oocyst wall protein gene and 18SSU rRNA gene in a single tube that can detect metabolically active cryptosporidial oocysts. The mRNA transcripts are the direct indicator of any actively replicating cell and they will help decipher the active stages of its lifecycle in a host. This diagnostic assay was standardized by computing transcript copy number-based limit of detection (LOD). For COWP and 18SSU rRNA genes, the LOD was 7.08 × 10⁰⁴ and 5.95 × 10⁰⁵ , respectively. During active infections, the oocyst wall protein will be active and so its COWP gene transcripts will act as a marker for active infection. While transcripts for 18SSU rRNA are constitutively expressed in cryptosporidial life cycle. This current diagnostic assay will be a quantitative marker that will help assess the active stages of Cryptosporidium infection in neonates. The disease dynamics will help better understand to formulate the control strategies and contain infection among healthy animals.

Cryptosporidiosis: From Prevention to Treatment, a Narrative Review

Cryptosporidiosis is a water- and food-borne zoonotic disease caused by the protozoon parasite of the genus Cryptosporidium. C. hominis and C. parvum are the main two species causing infections in humans and animals. The disease can be transmitted by the fecal-oral route as well as the respiratory route. The infective stage (sporulated oocysts) is resistant to different disinfectants including chlorine. Currently, no effective therapeutic drugs or vaccines are available to treat and control Cryptosporidium infection. To prevent cryptosporidiosis in humans and animals, we need to understand better how the disease is spread and transmitted, and how to interrupt its transmission cycle. This review focuses on understanding cryptosporidiosis, including its infective stage, pathogenesis, life cycle, genomics, epidemiology, previous outbreaks, source of the infection, transmission dynamics, host spectrum, risk factors and high-risk groups, the disease in animals and humans, diagnosis, treatment and control, and the prospect of an effective anti-Cryptosporidium vaccine. It also focuses on the role of the One Health approach in managing cryptosporidiosis at the animal-human-environmental interface. The summarized data in this review will help to tackle future Cryptosporidium infections in humans and animals and reduce the disease occurrence.

Simultaneous detection of less frequent waterborne parasitic protozoa in reused wastewater using amplicon sequencing and qPCR techniques

Waterborne parasitic protozoa (WPP) infections have a worldwide distribution and are a source for epidemic and endemic human diseases. Although a variety of protozoa are commonly detected in wastewater and cited as causative agents of outbreaks, effluents from wastewater treatment plants (WWTPs) used for irrigation can contain other pathogenic protozoa that are not currently being controlled. The lack of control on a routine basis using rapid and sensitive methods to detect these parasites in water may keep them under-recognized. This study focused on using molecular tools, 18 S rRNA amplicon-based sequencing and qPCR, to characterize WPP distribution in wastewater samples from urban WWTPs used for irrigation. A total of eight wastewater samples (from secondary and tertiary disinfection treatment effluents) were collected. Potentially pathogenic protozoa identified by 18 S rRNA sequencing and/or qPCR in the analyzed samples included Acanthamoeba spp., Blastocystis sp., Entamoeba coli, Entamoeba dispar, Entamoeba hartmanni, Giardia intestinalis assemblage A and Toxoplasma gondii Positive results by qPCR were in non-quantifiable levels. Blastocystis sp. was the most represented protozoa among the sequences retrieved from the amplicon sequencing. Blastocystis ST1 and ST2 were the most abundant subtypes among the obtained OTUs. Moreover, Blastocystis sp. ST3, ST4, ST6 and ST8 were also detected, although in lower abundances. Results of this study showed that WWTP effluents used for irrigation can provide a source of WPP.

Prevalence and Factors Associated with Cryptosporidium Infection in Calves in and around Nekemte Town, East Wollega Zone of Ethiopia

Purpose

Cryptosporidiosis, caused by a protozoan parasite of the genus Cryptosporidium, is a zoonotic disease that affects young animals and humans. The study was conducted from October 2020 to May 2021, with the objectives of estimating the prevalence of Cryptosporidium infection in calves and assessing the associated risk factors in Nekemte town, Ethiopia.

Methods

A cross-sectional study was adopted during the study period. Initially, 35 dairy farms were selected using a systematic study approach from which a total of 384 calves under the age of 12 months (75 calves from intensive, 51 from semi-intensive, and 258 from extensive dairy farms) were selected purposively for fecal sample collection. Fecal samples were collected directly from the rectum of each calf and tested for Cryptosporidium oocysts using Sheather's flotation and a modified Ziehl–Neelsen staining procedure. The data were analyzed using STATA statistical software version 13.

Results

Cryptosporidium infection was found in 53 of the 384 calves investigated, with an overall prevalence of 13.8% (95% CI = 8.1–17.6). Logistic regression analysis on the risk factors showed that types of farm, age, body condition scores, fecal consistency, types of feed, source of water, and farm hygiene were found to have a statistically significant influence on the shedding of Cryptosporidium oocysts by the calves (p < 0.05). Calves under the age of six months had a higher likelihood (OR = 2.7, 95% CI = 1.0–4.2, p < 0.001) of shedding the oocysts than the calves of 6 to 12 months of age. It was also confirmed that calves with poor body condition scores had a higher likelihood (OR = 2.6, 95% CI = 1.2–3.7, p=0.024) of shedding the Cryptosporidium oocysts than other ones. The likelihood of shedding a Cryptosporidium oocyst by the diarrheic calves was higher than by the nondiarrheic ones (OR = 3.1, p < 0.001). The infection was 2.6 times highest (16.8%, 31/185, 95% CI = 14.5–19.1, OR = 2.6, p=0.028) in calves feeding on grass alone, followed by milk and grass (15%) and milk (4.2%). Similarly, it was 2.2 times higher (18.5%, OR = 2.2, and p=0.002) in calves drinking river water than in calves drinking tap water. Moreover, calves kept under poor hygiene were more likely to shed Cryptosporidium oocysts (OR = 2.8, p=0.001) than calves kept under good hygiene.

Conclusion

In conclusion, cryptosporidiosis is one of the health problems of calves in and around Nekemte town, East Wollega zone. Our findings confirmed that risk factors such as types of farm, age, body condition scores, fecal consistency, types of feed, water source, and farm hygienic status were found to have a significant effect on the occurrence of Cryptosporidium infection in the calves. While the molecular-based study is required to be carried out aiming at species identification and the epidemiology of the parasite, particular attention should be paid to the control of the disease in the study area.

Zoonotic pathogens in wild muskoxen (Ovibos moschatus) and domestic sheep (Ovis aries) from Greenland

The present study aimed to estimate the prevalence of zoonotic pathogens Giardia duodenalis, Cryptosporidium spp., Toxoplasma gondii and Erysipelothrix in muskoxen (Ovibos moschatus) and sheep (Ovis aries) from Greenland. In 2017 and 2018, faecal samples were collected from wild muskoxen from three distinct populations (Zackenberg, Kangerlussuaq, and Ivittuut) and from domestic sheep from southwest Greenland. Blood samples were collected from muskoxen from Kangerlussuaq and Ivittuut and from sheep. Faecal samples were tested for specific DNA of G. duodenalis and Cryptosporidium spp., and blood samples were tested for antibodies against T. gondii and Erysipelothrix. The estimated prevalence of G. duodenalis was 0% (0/58), 17% (7/41) and 0% (0/55) in muskoxen from Zackenberg, Kangerlussuaq and Ivittuut, respectively, and 37% (16/43) in sheep. The estimated prevalence of Cryptosporidium was 0% (0/58), 2% (1/41), 7% (4/55) in muskoxen from Zackenberg, Kangerlussuaq, Ivittuut, respectively, and 2% (1/43) in sheep. Neither Giardia nor Cryptosporidium were detected in winter samples (0/78). Of the positive samples, Giardia from one muskox sample only was successfully typed as G. duodenalis assemblage A, and Cryptosporidium from two muskoxen was successfully typed as C. parvum, subtype IIdA20G1e. The estimated T. gondii seroprevalence was 2% (1/44) and 0% (0/8) in muskoxen from Kangerlussuaq and Ivittuut, respectively, and 1% (1/155) in sheep. The estimated Erysipelothrix seroprevalence was 2% (1/45) and 13% (1/8) in muskoxen from Kangerlussuaq and Ivittuut, respectively, and 7% (10/150) in sheep. The results of this study add to the scarce knowledge on zoonotic pathogens in the Arctic.

Clinical and Laboratory Diagnosis of Cryptosporidiosis among Children with Acute Gastroenteritis at a Tertiary Hospital, Cairo, Egypt

BACKGROUND

Most studies on gastroenteritis have focused on viral and bacterial infections, while gastroenteritis where intestinal protozoan parasites may have played a role has not been well studied. This study was therefore, designed to assess the frequency and several potential risk factors for Cryptosporidium infection among children suffering from acute gastroenteritis and presented to a tertiary hospital in Cairo, Egypt. Effectiveness of modified Ziehl-Neelsen (MZN) and nested polymerase chain reaction (nPCR) for Cryptosporidium detection were evaluated as well.

METHODS

A cross-sectional study was performed during the period from July 2018 to December 2018, where 100 human diarrheic stool samples were collected from children aged 3 months up to 12 years old presented to Ain Shams University Pediatrics Hospital, Cairo, Egypt with acute gastroenteritis. Demographic and clinical data were obtained from the participants. Initial parasite screening was done using the MZN staining method, and microscopically examined for Cryptosporidium infection, while genotyping was based on molecular diagnostic assays using nPCR and sequencing for selected samples.

RESULTS

The overall frequency of Cryptosporidium infection was 5% using light microscopy, while 19% of samples were positive by nPCR. Cryptosporidium hominis was the only detected genotype. Clinical picture among cases were not significant in comparison to patients with other causes of gastroenteritis.

CONCLUSION

Cryptosporidium infection is more common below 5 years of age; however, clinical data are not enough for suspicion of infection. Nucleic acid-based methods are more sensitive and specific despite the high cost in developing countries. However, real estimation of Cryptosporidium disease burden is of an outmost importance to achieve prevention and detection of the Cryptosporidium species genetic diversity. Lay summaryCryptosporidium is a protozoan, which causes gastroenteritis in humans. It is most common below 5 years of age; however, diarrhea and vomiting characteristics are not different from other causes of gastroenteritis. General diagnostic methods are inadequate for detection of these infections. Nested polymerase chain reaction (nPCR) and sequencing are accurate methods for pathogen detection and species verification. Our study included 100 Egyptian children with acute gastroenteritis. The overall frequency of Cryptosporidium infection was 5% using light microscopy, while 19% of samples were positive by nPCR. The clinical picture of the children presenting with this disease was not significantly different from those presenting with gastroenteritis due to other causes. This emphasizes the importance of proper diagnosis to know the true burden of the disease.

Zoonotic enteric parasites in Mongolian people, animals, and the environment: Using One Health to address shared pathogens

BACKGROUND

Cryptosporidium spp. and Giardia duodenalis are important zoonotic enteric pathogens of One Health concern for humans, animals, and the environment. For this study, we investigated parasite prevalence and risk factors among rural, peri-urban, and urban households and environments of Mongolia.

METHODS

This cross-sectional study implemented a household risk factor survey at 250 home sites along with sample collection from humans, animals, flies, and drinking water. Multiplex real-time PCR analysis was conducted to look for Cryptosporidium spp. and/or Giardia duodenalis within household samples.

RESULTS

Lab analysis found one or both zoonotic parasites at 20% of the participating households (51/250). Human samples had a parasite prevalence of 6.4% (27/419), domestic animals at 3.3% (19/570), pooled filth flies at 14.8% (17/115), and drinking water samples at 2% (5/250). Parasite presence at the household was significantly associated with a household's use of an improved drinking water source (OR 0.27; CI 0.12-0.61; p = < 0.01), having an indoor handwashing site (OR 0.41; CI 0.19-0.92; p = 0.03), domestic animal ownership (OR 2.40; CI 1.02-5.65; p = 0.05), and rural location (OR 0.50; CI 0.25-0.98; p = 0.04). Household use of an improved drinking water source remained significant in the multivariate model (OR 0.16; CI 0.04-0.68; p = 0.01).

CONCLUSION

In Mongolia, public and veterinary health are intertwined, particularly for rural herding households. Increased access to safe water, sanitation and hygiene infrastructure could help prevent further transmission of zoonotic enteric parasites. Public health interventions, policy and messaging should utilize a One Health framework employing joint leadership from local human and animal health sectors.

Cryptosporidium Infection and Associated Risk Factors among Cattle in the Central Region of Ghana

Cryptosporidium species infects a wide number of animals including livestock all over the world. The current study was done to determine the prevalence and risk factors of Cryptosporidium infection among cattle in the Central Region of Ghana. Two hundred and eighty-seven (287) faecal samples were randomly collected from animals on eight cattle farms in four districts across two agroecological zones. A commercial enzyme-linked immunosorbent assay kit (CoproELISA, Savyon® Diagnostics Ltd., Israel) for Cryptosporidium was used in the detection of Cryptosporidium antigens in faecal samples. Characteristics of the animals such as age, sex, and location, as well as consistency of faecal samples, were collected. Pearson's chi-square or Fisher's exact test was used to determine the association between explanatory variables and Cryptosporidium infection while a logistic regression model was also used to determine the risk of infection. The overall prevalence of Cryptosporidium infection was 23.7% (95% CI, 18.7-28.6). Prevalence was significantly higher (p = 0.049) among cattle aged 12-month old and above compared to those under 12 months of age. Among the four districts in the study area, Cape Coast metropolis recorded a significantly higher prevalence (60.5%; CI, 49.3-71.8), (p < 0.001) compared to the other three. Furthermore, a significant association was observed between the consistency of faecal samples and Cryptosporidium infection (p = 0.042). The prevalence of Cryptosporidium infection was also significantly higher among cattle from the coastal savanna zone (26.9%; 95% CI, 21.0-32.8) compared to those from the semideciduous forest area (p = 0.017). Cattle in the forest zone had a lower risk of being infected with the parasite compared to those from the coastal savanna zone (OR 0.408; 95% CI, 0.182-0.915). In conclusion, Cryptosporidium was prevalent among cattle in the Central Region of Ghana. A higher prevalence of Cryptosporidium infection occurred in older animals and among animals in the coastal agroecological zone. The area of location and age of animals were identified as risk factors for Cryptosporidium infection in the Central Region of Ghana.

Zakażenia przewodu pokarmowego w XXI wieku w Polsce i na świecie

Na początku XXI wieku wciąż istnieje ogólnoświatowy problem zakażeń przewodu pokarmowego we wszystkich grupach wiekowych ludności. Za najpowszechniejszy czynnik etiologiczny chorób biegunkowych na świecie przenoszony przez skażoną żywność uważany jest Norovirus oraz bakterie z rodzaju Salmonella i Campylobacter, jednak za największą liczbę nieżytów żołądkowo-jelitowych odpowiadają rotawirusy. Ciągle terenami endemicznymi ciężkich zakażeń pokarmowych jest Afryka, Azja Południowo-Wschodnia, Ameryka Łacińska oraz wschodnia część Basenu Morza Śródziemnego. Na tych terenach utrzymują się „stare” czynniki etiologiczne biegunek, takie jak np.: Vibrio cholerae, Salmonella Typhi, Salmonella Paratyphi. Grupą szczególnie narażoną na infekcje pokarmowe pozostają dzieci <5. roku życia. Głównym czynnikiem etiologicznym biegunek w tej grupie wiekowej – zarówno w krajach rozwiniętych, jak i rozwijających się – są rotawirusy. Odpowiadają one za 500 tys. zgonów rocznie. Polska ze względu na ograniczone standardy diagnostyczne, epidemiologicznie różni się częstotliwością występowania poszczególnych patogenów biegunkowych od pozostałych krajów. Dotyczy to niższej zapadalności na zakażenia o etiologiach: Campylobacter, Norovirus, Shigella. Dominującym czynnikiem zakażeń pokarmowych o podłożu bakteryjnym w kraju są pałeczki Salmonella, natomiast wirusowym rotawirusy. Wiedza na temat chorób infekcyjnych układu pokarmowego może być w XXI w. na nowo sformułowana, a lista czynników etiologicznych poszerzona, sprzyjają temu zaś badania mikrobioty jelit oraz powszechne stosowanie nowych technik diagnostycznych m.in. spektometrii mas i real-time PCR.

Contamination of coins and banknotes as sources of transmission of parasitic pathogens: a pilot study from Iran

OBJECTIVE

This study was conducted to determine the presence, type, and rate of parasitic contamination in Iranian currencies.

STUDY DESIGN

This was a cross-sectional study.

METHODS

Coins and banknotes of different denominations were randomly collected from sellers and markets in Tabriz, Northwest of Iran, for examining parasitic contamination.

RESULTS

Entamoeba coli and Giardia intestinalis were the most identified species of parasites in this study. Other parasites detected were Cryptosporidium parvum, Ascaris lumbricoides, Entamoeba histolytica, Fasciola hepatica, and Toxocara cati. A high rate of parasitic contamination was found in banknotes compared with coins, and a statistically significant association was found between parasitic contamination and the apparent condition of the currencies. The notes of lower denominations showed the highest contamination rates. The highest parasitic contamination was found in coins and banknotes obtained from public toilet services, butchers, and beggars.

CONCLUSIONS

The findings emphasize the role of circulating coins and banknotes in the risk of pathogenic parasite transmission.

Detection of Cryptosporidium and Giardia in foods of plant origin in North-Western Greece

Giardia and Cryptosporidium are recognized as leading causes of waterborne and foodborne diarrhoeal disease with worldwide distribution. The study aimed to determine the protozoan contamination of various foods of plant origin. A total of 72 samples from 27 different varieties of fresh vegetables and fruits were collected from supermarkets and open markets in North-Western Greece and were examined using conventional diagnostic methods. Two out of 72 (2.8%) samples were found positive for Cryptosporidium oocysts, while no sample was found to be positive for Giardia cysts. The results show the presence of protozoan contamination in foods of plant origin, which may constitute a potential health hazard.

Prevalence of Intestinal Parasitic Infections among the Bulgarian Population Over a Three Year Period (2015 - 2017)

The aim of the present study is to perform a retrospective analysis of the prevalence of intestinal parasitic infections among the Bulgarian population over the period 2015 - 2017. The study involved all Bulgarians and foreign nationals residing in the country who had been tested for intestinal protozoa and helminths. A total of 23,785 infections have been revealed, of which 17,712 (74.47 %) were helminth and 6,073 (25.53 %) protozoan invasions. Enterobiasis was found to be the most prevalent among patients infected with intestinal helminths (81.75 %), while giardiasis (62.05 %) was the most common among those diagnosed with protozoan infections. In spite of improved living conditions and increasing public health awareness, parasitic diseases in general, and intestinal parasitic infections in particular, still represent a significant part of the overall morbidity in Bulgaria, thus posing a major issue for the public health care system.

Detection of Giardia spp. with formalin/ether concentration in Brassica oleracea (cabbage) and Lactuca sativa (lettuce)

Methods to detect protozoa are needed for food safety monitoring. We evaluated protocols to recover Giardia spp. cysts in Brassica oleracea (cabbage) and Lactuca sativa (lettuce) and then detection was performed by concentrating with formalin/ether solutions and microscopy or immunofluorescence or DNA amplification via PCR. To evaluate this methodology, G. duodenalis cysts were inoculated in triplicate (10 cysts) in 35-g samples of lettuce and cabbage. The method obtaining the highest percentage of recovery in cabbage was sulfamic acid solution plus stirring with stomacher (47.7% ± 7.5). For lettuce, the best method was glycine solution plus stirring with stomacher (46.6% ± 5.3). Inter-observer agreement was of 0.99. Giardia was detected by amplifying specific sequences for the DNA coding SSU rRNA. In 27 lettuce samples and 27 cabbage samples, obtained from supermarkets and street vendors, two lettuce samples (7.4%) and one cabbage sample (3.7%) were positive for Giardia via PCR assay and were sequenced, determining that they were two of assemblage B and one of lettuce to assemblage E. This method is proposed to detect Giardia in vegetables by PCR detection, enabling public health authorities to identify genotypes circulating in food, which will help to establish measures that reduce outbreaks of parasitic diseases associated with contaminated food.

Cryptosporidium proventriculi sp. n. (Apicomplexa: Cryptosporidiidae) in Psittaciformes birds

Cryptosporidiosis is a common parasitic infection in birds that is caused by more than 25 Cryptosporidium species and genotypes. Many of the genotypes that cause avian cryptosporidiosis are poorly characterized. The genetic and biological characteristics of avian genotype III are described here and these data support the establishment of a new species, Cryptosporidium proventriculi. Faecal samples from the orders Passeriformes and Psittaciformes were screened for the presence of Cryptosporidium by microscopy and sequencing, and infections were detected in 10 of 98 Passeriformes and in 27 of 402 Psittaciformes. Cryptosporidium baileyi was detected in both orders. Cryptosporidium galli and avian genotype I were found in Passeriformes, and C. avium and C. proventriculi were found in Psittaciformes. Cryptosporidium proventriculi was infectious for cockatiels under experimental conditions, with a prepatent period of six days post-infection (DPI), but not for budgerigars, chickens or SCID mice. Experimentally infected cockatiels shed oocysts more than 30 DPI, with an infection intensity ranging from 4,000 to 60,000 oocysts per gram (OPG). Naturally infected cockatiels shed oocysts with an infection intensity ranging from 2,000 to 30,000 OPG. Cryptosporidium proventriculi infects the proventriculus and ventriculus, and oocysts measure 7.4 × 5.8 μm. None of the birds infected C. proventriculi developed clinical signs.

Prevalence and multilocus genotypes of Giardia duodenalis infecting pigs in Ogun state, Nigeria

Giardia duodenalis is an intestinal flagellated protozoan parasite that is infectious to humans and a wide range of animals worldwide. While varying prevalence rates have been reported in pigs worldwide, there are currently no published reports on the genotypes of Giardia infecting pigs in any African country. The present study is on the prevalence and genotypes of G. duodenalis in 209 pigs raised on four farms in Ogun State Nigeria. Using an enzyme-linked immunosorbent assay (ELISA) kit, Giardia duodenalis coproantigens were detected on all farms and in 25.4% (53/209) of pigs sampled. However, there was no significant influence (p > 0.05) of age, sex and stool consistencies of the pigs on the distribution of the infection. Genotyping of Giardia duodenalis in all ELISA-positive samples, achieved by the amplification of the small subunit ribosomal RNA (ssu rRNA), glutamate dehydrogenase (gdh), triosephosphate isomerase (tpi) and beta giardin (bg) genes, identified 14 and 37 assemblage B and E isolates respectively while mixed infection by both assemblages was recorded in two isolates. Novel nucleotide substitutions were identified in four assemblage B isolates at the ssu rRNA locus. Genetic diversity was observed among the assemblage B isolates after multiple alignment analyses of the gdh, tpi and bg sequences whereby sub-assemblages BII (n = 2), BIII (n = 9) and BIV (n = 3) were identified. The assemblage B isolates from pigs in this study were phylogenetically related to isolates from humans, marmoset and cattle while the assemblage E isolates were related to isolates from sheep, goats and cattle. These findings suggest that pigs in southwest Nigeria predominantly harbour G. duodenalis isolates that could be infectious to other animal species and to a lesser extent, isolates that may be of zoonotic importance.

Molecular genotyping, diversity studies and high-resolution molecular markers unveiled by microsatellites in Giardia duodenalis

BACKGROUND

Giardia duodenalis (synonyms G. lamblia and G. intestinalis) is an enteric protozoan parasite of a wide range of mammalian hosts, including humans and various domestic and wild animals. There is considerable genetic variability in G. duodenalis and isolates of this parasite have been divided into eight genetic assemblages. Microsatellites markers can be used to discriminate isolates with a high level of sensitivity. This study was conducted to identify and characterize genomic microsatellites (simple sequence repeats-SSRs), sequences of one- to six-nucleotide motifs repeated in tandem, present in the available genomes of G. duodenalis and to develop new markers that can serve as a tool for detection and for characterizing the genetic diversity of this parasite.

METHODOLOGY/ PRINCIPAL FINDINGS

For each genetic assemblage, polymorphism levels for the microsatellite markers were evaluated. After performing the analysis using the MISA and SciRoKo software, 1,853 simple sequence repeats (SSRs) were identified. In all the genomes, trinucleotide repeats were the most common class followed by tetranucleotide. Many of the SSR loci are assemblage-specific, and 36 SSR loci shared among all the genomes were identified. Together with hypothetical proteins, variant-specific surface proteins represented nearly half of the annotated SSR loci. The results regarding the most common repeat among the SSRs led us to infer that positive selection occurred to avoid frameshift mutations. Additionally, based on inter- and intra-genetic assemblages polymorphism analyses, we unveiled previously undetected genetic variation, indicating that the microsatellite markers we developed are useful molecular tools for epidemiological inferences based on population genetics patterns and processes.

CONCLUSIONS

There is increasing demand for the development of new molecular markers and for the characterization of pathogens at a higher resolution level. In this study, we present 60 G. duodenalis microsatellites markers that exhibited high polymerase chain reaction (PCR) amplification efficiency among the different genetic assemblages. Twenty of these markers presented nucleotide sequence polymorphisms and may be used as a genotyping tool. The monomorphic markers can be used for the detection of the parasite at the species and genetic assemblage level. These polymorphic markers revealed a genetic diversity that was previously undetectable, thus they can be considered valuable molecular tools for high resolution markers in future studies investigating Giardia and may also be used for epidemiological inferences based on populations genetics patterns and processes.

Giardia duodenalis in the UK: current knowledge of risk factors and public health implications

Giardia duodenalis is a ubiquitous flagellated protozoan parasite known to cause giardiasis throughout the world. Potential transmission vehicles for this zoonotic parasite are both water and food sources. As such consumption of water contaminated by feces, or food sources washed in contaminated water containing parasite cysts, may result in outbreaks. This creates local public health risks which can potentially cause widespread infection and long-term post-infection sequelae. This paper provides an up-to-date overview of G. duodenalis assemblages, sub-assemblages, hosts and locations identified. It also summarizes knowledge of potential infection/transmission routes covering water, food, person-to-person infection and zoonotic transmission from livestock and companion animals. Public health implications focused within the UK, based on epidemiological data, are discussed and recommendations for essential Giardia developments are highlighted.

Socio-Behavioral Risk Factors Associated with Cryptosporidiosis in HIV/AIDS Patients Visiting the HIV Referral Clinic at Cape Coast Teaching Hospital, Ghana

Objective:

To identify the socio-behavioral risk factors associated with cryptosporidiosis among HIV/AIDS patients with chronic diarrhea symptoms visiting the HIV referral clinic at Cape Coast Teaching Hospital, Ghana.

Methods:

A cross-sectional study was conducted among 50 HIV/AIDS patients with recurrent diarrhea. Questionnaires were administered to collect social and behavioral risk factors associated with Cryptosporidium and other opportunistic protozoan parasitic infections in HIV patients. Stool samples were collected for the diagnosis of enteric protozoan pathogens using modified Ziehl-Neelsen and acid-fast staining methods. CD4⁺ cells counts of study subjects were obtained from patients clinical records. The data obtained were analyzed using Pearson chi-square and multivariate-adjusted statistics tool on SPSS 16 for Windows.

Results:

Twenty-seven (54%) of the subjects were infected with enteric protozoan pathogens. The prevalences of Cryptosporidium, Cyclospora and Microsporidium infections were 46%, 32% and 16%, respectively. Cryptosporidium infection was significantly associated with drinking water (ײ=13.528, p<0.001), Cyclospora was associated with the type of drinking water (ײ=14.931, p<0.001) and toilet facilities used by the study subjects (ײ=12.463, p<0.01), whiles Microsporidium infection was associated with hand washing behavior (ײ=12.463, p<0.01). Enteric protozoans were frequently encountered among subjects with CD4+ T-cell count <200 cells/mm³. However, coinfection of Cyclospora spp & Cryptosporidium spp was not observed in CD4⁺ cell count <200 and >500 cells/mm^3. Multivariate analysis showed that the risk factor for Cryptosporidium infection among HIV/AIDS patients was the source of drinking water (pipe borne water 76.2% prevalence: sachet water 25%; OR=0.10, 95%CI: 0.03-0.39, p<0.001).

Conclusion:

We report the risk factor for exposure of Cryptosporidium infection among HIV/AIDS patients for the first time in Ghana. The contamination of drinking water by protozoan parasites should be a public health concern. These results provide the stepping block to understand the transmission dynamics of Cryptosporidium and other opportunistic pathogens in HIV/AIDS infected patients in Ghana.

Opportunistic and non-opportunistic intestinal parasites in HIV/ AIDS patients in relation to their clinical and epidemiological status in a specialized medical service in Goiás, Brazil

Patients infected with the Human Immunodeficiency Virus (HIV) often have opportunistic infections, among which strongyloidiasis and coccidiosis are the most common parasitic infections that aggravate their health status. This study examined the prevalence of intestinal parasites, particularly of Strongyloides stercoralis and intestinal coccidia in patients with the Human Immunodeficiency Virus (HIV)/ Acquired Immunodeficiency Syndrome (AIDS) who were treated at the Specialized Assistance Service (SAE) of Jataí, State of Goiás, Brazil, and analyzed its correlation with clinical, laboratory, and socio-epidemiological parameters. A total of 270 stool samples were analyzed by the Lutz technique, Rugai's method, Agar Plate Culture, Ritchie's method and specific staining, Ziehl-Neelsen modified technique, Kinyoun's method and the rapid safranin method. The prevalence of intestinal parasites was 28.88% including 3.8% of S. stercoralis, Cryptosporidium sp. and Cystoisospora belli. There was a significant positive correlation between intestinal parasites and the clinical status and the use of antiretroviral therapy (ART), smoking, CD4+ lymphocyte counts and sexual orientation. In conclusion, the widespread use of antiretroviral therapy and health assistance contributed to the low prevalence of S. stercoralis and coccidiosis in patients with HIV/ AIDS who were followed up at the SAE.

Prevalence and risk factors associated with Giardia duodenalis infection in dairy cattle of Chitwan, Nepal

Livestock farming has been an integral part of Nepalese agriculture systems since time immemorial. Giardia duodenalis is a cosmopolitan intestinal parasite present in a wide range of hosts. Very little or no information is reported on the prevalence of giardiasis in livestock of Nepal. This study was done during Jan 18 to July 19, 2014 to determine the prevalence and associated risk factors of Giardia duodenalis infection in dairy cattle of Chitwan, Nepal. A total of 96 fresh fecal samples were collected from various dairy pocket areas and were transferred to collection bottles with 10% formalin. Wet smears of the samples were prepared, stained with lugol's iodine and then viewed under microscope at 400× magnification. The overall prevalence was found to be 44.79% (43/96). Based on the risk factors assessment survey, age was found to be significantly associated with the prevalence of Giardia duodenalis. The prevalence was found significantly (P < 0.05) higher in 1-6 months age group compared to > 3 years. Similarly, higher prevalence was found in diarrheic animals compared to their counterparts (P < 0.05). Though higher prevalence was recorded in unhygienically housed animals, it was statistically non-significant (P < 0.05). Giardiasis should be considered as an important cause of diarrhea and further advanced diagnostic approaches should be employed for the confirmation of giardiasis in dairy cattle.

An advanced uracil DNA glycosylase-supplemented loop-mediated isothermal amplification (UDG-LAMP) technique used in the sensitive and specific detection of Cryptosporidium parvum, Cryptosporidium hominis, and Cryptosporidium meleagridis in AIDS patients

The rapid and accurate detection of Cryptosporidium spp. is critically important for the prevention and timely treatment of cryptosporidiosis in AIDS patients (APs). This study was conducted to examine a UDG-LAMP technique for the first time to diagnose cryptosporidiosis in APs. After collecting demographic and clinical data, three stool samples were collected from the participants (120 volunteering APs). The microscopic examination of stained smears using the acid-fast method and the UDG-LAMP assay were performed for each sample. 10% of APs were infected with Cryptosporidium spp. The number of detected cryptosporidiosis cases using the acid-fast staining and UDG-LAMP methods were significantly different (P < 0.001). Diarrhea and weight loss were found to be significantly associated with cryptosporidiosis in patients (P < 0.05). The pretreatment of LAMP reagents with UDG successfully eliminated the likelihood of product re-amplification remaining from previous reactions. The UDG-LAMP technique could detect cryptosporidiosis in APs with high sensitivity and rapidity without carryover contamination.

Towards enhanced automated elution systems for waterborne protozoa using megasonic energy

Continuous and reliable monitoring of water sources for human consumption is imperative for public health. For protozoa, which cannot be multiplied efficiently in laboratory settings, concentration and recovery steps are key to a successful detection procedure. Recently, the use of megasonic energy was demonstrated to recover Cryptosporidium from commonly used water industry filtration procedures, forming thereby a basis for a simplified and cost effective method of elution of pathogens. In this article, we report the benefits of incorporating megasonic sonication into the current methodologies of Giardia duodenalis elution from an internationally approved filtration and elution system used within the water industry, the Filta-Max®. Megasonic energy assisted elution has many benefits over current methods since a smaller final volume of eluent allows removal of time-consuming centrifugation steps and reduces manual involvement resulting in a potentially more consistent and more cost-effective method. We also show that megasonic sonication of G. duodenalis cysts provides the option of a less damaging elution method compared to the standard Filta-Max® operation, although the elution from filter matrices is not currently fully optimised. A notable decrease in recovery of damaged cysts was observed in megasonic processed samples, potentially increasing the abilities of further genetic identification options upon isolation of the parasite from a filter sample. This work paves the way for the development of a fully automated and more cost-effective elution method of Giardia from water samples.

The first study of molecular prevalence and species characterization of Cryptosporidium in free-range chicken (Gallus gallus domesticus) from Brazil

Rearing free-range chicken is based on grazing feeding patterns, and these animals could be potential environmental contaminants of Cryptosporidium oocysts for humans and other animals. Therefore, the present study aimed to evaluate the molecular prevalence of Cryptosporidium spp. in free-range chickens from Brazil. A total of 351 fecal samples from chickens were examined from 20 farms. For detection of Cryptosporidium spp., 18S rRNA gene fragments were amplified using a nested PCR reaction. Positive samples were sent for sequencing. The overall prevalence of Cryptosporidium was 25.6% (95% CI = 21.2% - 30.6%). Sequencing of the amplified fragments allowed for the identification of three species: C. meleagridis in 57 (62.6%), C. baileyi in 15 (16.4%), C. parvum in 3 (3.2%) samples, and a new Cryptosporidium genotype (C. genotype BrPR1) in 3 (3.2%) samples. Cryptosporidium genotype BrPR1 has not yet been classified as a species, and its host spectrum is not known. Cryptosporidium, including zoonotic species, exists at a high prevalence in free-range chickens within the region studied.

Gastrointestinal parasites in feral cats and rodents from the Fernando de Noronha Archipelago, Brazil

Gastrointestinal parasites are important pathogens affecting animals, some of them are of medical and veterinary concern. Although the dynamic of parasitic infections is a complex phenomenon that has been studied under experimental conditions, it shows several gaps in knowledge, especially in insular regions where a confined population of animals and parasites co-exists. In this study was assessed the parasitism by endoparasite gastrointestinal in feral cats (n = 37) and rodents (n = 30) from the Fernando de Noronha Archipelago; in addition, the risk of human infection and ecological implications of these findings were discussed. Out of all samples analysed, 100% scored positive for the presence of gastrointestinal parasites in both feral cats and rodents. A total 17 genera and/or species of endoparasite gastrointestinal were identified, Ancylostoma sp., Strongyloides sp., Trichuris campanula and Toxocara cati were the parasites more frequently in feral cats. In rodents Eimeria sp., Strongyloides sp. and Trichuris muris were parasites more frequently herein detected. Human population living in this area are at risk of parasite infections due to the population of rodents and feral cats in the archipelago.

Multiple identification of most important waterborne protozoa in surface water used for irrigation purposes by 18S rRNA amplicon-based metagenomics

Understanding waterborne protozoan parasites (WPPs) diversity has important implications in public health. In this study, we evaluated a NGS-based method as a detection approach to identify simultaneously most important WPPs using 18S rRNA high-throughput sequencing. A set of primers to target the V4 18S rRNA region of WPPs such as Cryptosporidium spp., Giardia sp., Blastocystis sp., Entamoeba spp, Toxoplasma sp. and free-living amoebae (FLA) was designed. In order to optimize PCR conditions before sequencing, both a mock community with a defined composition of representative WPPs and a real water sample inoculated with specific WPPs DNA were prepared. Using the method proposed in this study, we have detected the presence of Giardia intestinalis, Acanthamoeba castellanii, Toxoplasma gondii, Entamoeba histolytica and Blastocystis sp. at species level in real irrigation water samples. Our results showed that untreated surface irrigation water in open fields can provide an important source of WPPs. Therefore, the methodology proposed in this study can establish a basis for an accurate and effective diagnostic of WPPs to provide a better understanding of the risk associated to irrigation water.

Detection of Giardia intestinalis in water samples collected from natural water reservoirs and wells in northern and north-eastern Poland using LAMP, real-time PCR and nested PCR

Giardia intestinalis is a protozoan parasite, transmitted to humans and animals by the faecal-oral route, mainly through contaminated water and food. Knowledge about the distribution of this parasite in surface water in Poland is fragmentary and incomplete. Accordingly, 36 environmental water samples taken from surface water reservoirs and wells were collected in Pomerania and Warmia-Masuria provinces, Poland. The 50 L samples were filtered and subsequently analysed with three molecular detection methods: loop-mediated isothermal amplification (LAMP), real-time polymerase chain reaction (real-time PCR) and nested PCR. Of the samples examined, Giardia DNA was found in 15 (42%) samples with the use of LAMP; in 12 (33%) of these samples, Giardia DNA from this parasite was also detected using real-time PCR; and in 9 (25%) using nested PCR. Sequencing of selected positive samples confirmed that the PCR products were fragments of the Giardia intestinalis small subunit rRNA gene. Genotyping using multiplex real-time PCR indicated the presence of assemblages A and B, with the latter predominating. The results indicate that surface water in Poland, as well as water taken from surface wells, may be a source of Giardia strains which are potentially pathogenic for humans. It was also demonstrated that LAMP assay is more sensitive than the other two molecular assays.

Keeping it cool: Survival of Giardia cysts and Cryptosporidium oocysts on lettuce leaves

Fresh produce has been recognized as a vehicle for transmission of protozoan parasites for many years, and there are numerous publications regarding their occurrence on such foodstuffs, indicating their potential importance as foodborne parasites. Nevertheless, few studies have been published regarding the effectiveness of this transmission route, and whether contamination is likely to result in transmission. The purpose of this study was to assess the viability of Cryptosporidium oocysts and Giardia cysts, two protozoa associated with both waterborne and foodborne transmission, by spiking fresh produce (lettuce leaves) with viable transmission stages and determining changes in viability. These investigations were performed under different conditions and over time spans that may be used in a regular household; a fridge at 4°C, under ambient temperatures exposed to natural cycles of light during night and day, and inside a cupboard to ensure no light exposure, for a duration of up to two weeks, or as long as the produce remained visually palatable. The major finding from this study is that whereas both Cryptosporidium oocysts and Giardia cysts survive well when kept moist and refrigerated, survival of Giardia cysts was abrogated on lettuce at room temperature. Indeed, almost 50% die-off of Giardia cysts was recorded within the first 24h. Cryptosporidium oocysts had a stable viability throughout the experiment under all the conditions investigated, indicating that fresh produce is a suitable transmission vehicle for Cryptosporidium, even if contamination occurs on-farm and the parasites are exposed to non-favourable storage conditions, as may be common in developing countries. Giardia cysts were not as robust as Cryptosporidium oocysts, and would be probably unlikely to survive under ambient storage conditions on-farm, during sale, or at home. However, if kept refrigerated, then some contaminating Giardia cysts may remain viable and therefore may pose a threat to the consumer. Thus, as the cold chain for transport and storage of fresh produce improves, it is important that similar improvements are implemented to reduce the contamination of fresh produce with parasite transmission stages.

Molecular characterisation of protist parasites in human-habituated mountain gorillas (Gorilla beringei beringei), humans and livestock, from Bwindi impenetrable National Park, Uganda

Background

Over 60 % of human emerging infectious diseases are zoonotic, and there is growing evidence of the zooanthroponotic transmission of diseases from humans to livestock and wildlife species, with major implications for public health, economics, and conservation. Zooanthroponoses are of relevance to critically endangered species; amongst these is the mountain gorilla (Gorilla beringei beringei) of Uganda. Here, we assess the occurrence of Cryptosporidium, Cyclospora, Giardia, and Entamoeba infecting mountain gorillas in the Bwindi Impenetrable National Park (BINP), Uganda, using molecular methods. We also assess the occurrence of these parasites in humans and livestock species living in overlapping/adjacent geographical regions.

Results

Diagnostic PCR detected Cryptosporidium parvum in one sample from a mountain gorilla (IIdA23G2) and one from a goat (based on SSU). Cryptosporidium was not detected in humans or cattle. Cyclospora was not detected in any of the samples analysed. Giardia was identified in three human and two cattle samples, which were linked to assemblage A, B and E of G. duodenalis. Sequences defined as belonging to the genus Entamoeba were identified in all host groups. Of the 86 sequence types characterised, one, seven and two have been recorded previously to represent genotypes of Cryptosporidium, Giardia, and Entamoeba, respectively, from humans, other mammals, and water sources globally.

Conclusions

This study provides a snapshot of the occurrence and genetic make-up of selected protists in mammals in and around BINP. The genetic analyses indicated that 54.6% of the 203 samples analysed contained parasites that matched species, genotypes, or genetic assemblages found globally. Seventy-six new sequence records were identified here for the first time. As nothing is known about the zoonotic/zooanthroponotic potential of the corresponding parasites, future work should focus on wider epidemiological investigations together with continued surveillance of all parasites in humans, other mammals, the environment, and water in this highly impoverished area.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-017-2283-5) contains supplementary material, which is available to authorized users.

First detection and genotyping of Giardia intestinalis in stool samples collected from children in Ghazni Province, eastern Afghanistan and evaluation of the PCR assay in formalin-fixed specimens

It is estimated that faecal-orally transmitted diseases are common in Afghanistan, as a consequence of poor hygienic standards of life and widespread contamination of water and food with both human and animal faeces. However, there is little information in the literature concerning infections caused by intestinal parasites in the Afghan population. In this study, we report the occurrence of Giardia intestinalis assemblages (A and B) in formalin-fixed stool samples collected from 245 Afghan schoolchildren living in Ghazni Province in eastern Afghanistan. Detection of the parasite’s DNA and genotyping was performed using real-time PCR, specific to the β-giardin gene of G. intestinalis. Positive results were recorded in 52 (21.2%) samples. Genotyping was successful in 39 faecal samples and showed the predominance of assemblage B of G. intestinalis in this population (15 assemblage A and 24 assemblage B). Co-infection with both genotypes A and B was detected in four samples. Additionally, we evaluated the effect of 10% buffered formalin fixative on the detection of G. intestinalis DNA using real-time PCR and nested PCR characterised by different lengths of PCR products (74 and 479 bp, respectively). The human faeces containing the Giardia cysts were tested for 16 weeks. Amplification of G. intestinalis DNA with real-time PCR was possible up to 6 weeks of preservation of stool sample in formalin, compared to only 2 weeks with nested PCR. This suggests that real-time PCR is a more suitable tool in cases where stool samples have to be kept in formalin for longer periods of time.

Molecular diagnosis and characterization of Cryptosporidium spp. in turkeys and chickens in Germany reveals evidence for previously undetected parasite species

A total of 256 fecal specimens were randomly collected from farmed poultry in Germany and screened for the presence of Cryptosporidium spp. by PCR and further characterized by direct automated DNA sequencing. Using a nested PCR amplifying approximately 830 bp 18S rDNA fragment, 7.03% (n = 18) of the samples were Cryptosporidium-positive. In detail, Cryptosporidium was detected in 9.3% (8/86) of turkeys, 5.7% (9/158) of broilers and 8.3% (1/12) of layers. After DNA sequencing, Cryptosporidium parvum the most frequently observed species was identified in 5.1% (13/256) of all poultry species, including 8.1% (7/86) of turkeys, 3.2% (5/158) of broilers and 8.3% (1/12) of layers. Cryptosporidium baileyi was detected in 1.3% (2/256) of the broilers only. Three novel unclassified Cryptosporidium spp. were detected in 1.2% (1/86) of turkeys and 1.3% (2/158) of broilers. The infection rate was high in 13-20 week old turkeys, 1-6 weeks old broilers and >20 weeks old layers but differences between age groups were not significant. This is the first study in Germany uses molecular methods for the detection of Cryptosporidium in poultry. The results indicate that Cryptosporidium parasites are common among broilers and turkeys in Germany. Considering the large size of the poultry industry, the large amount of poultry meat that is consumed and the fact that C. parvum is also the most common Cryptosporidium parasite in humans, poultry might also be a source of human infections.

No molecular epidemiological evidence supporting household transmission of zoonotic Giardia duodenalis and Cryptosporidium spp. from pet dogs and cats in the province of Álava, Northern Spain

The role of pet dogs and cats as suitable source of human infections by the diarrheagenic protozoan parasites Giardia duodenalis and Cryptosporidium spp. has been a topic of intense debate for long time and still remains a largely unsolved problem. In this cross-sectional molecular epidemiological survey we attempted to investigate whether zoonotic (or zooanthroponotic) disease transmission was occurring among humans and domestic dogs and cats sharing the same spatial and temporal setting in both rural and urban areas of the province of Álava, Northern Spain. A total of 268 (including 179 human, 55 canine, and 34 feline) individual faecal specimens were obtained from 63 family households during February-March and November-December 2014. Detection of G. duodenalis cysts and Cryptosporidium spp. oocysts was achieved by direct fluorescence microscopy (DFAT) and PCR-based methods targeting the small subunit (SSU) ribosomal RNA gene of the parasites. Giardia-positive isolates were subsequently sub-genotyped at the glutamate dehydrogenase (GDH) and β-giardin (BG) genes. Overall, G. duodenalis infections were identified in 3.4% (6/179) of humans, 29% (16/55) of dogs, and 5.9% (2/34) of cats, respectively. Cryptosporidium spp. infections were detected in 1.1% (2/179) of humans, 5.5% (3/55) of dogs, and 8.8% (3/34) of cats, respectively. Simultaneous infections in human and canine/feline hosts by G. duodenalis or Cryptosporidium spp. were only demonstrated in a single household in which a cat and its owner tested positive for Cryptosporidium by DFAT, but this result could not be confirmed by SSU-PCR. Infections were homogeneously distributed among the studied human or animal populations irrespectively of their sex, age group, or geographical region of origin. Inadequate washing of raw vegetables and fruits was the only risk factor significantly associated to a higher likelihood of having human giardiosis/cryptosporidiosis. Molecular characterization of G. duodenalis isolates revealed the presence of sub-assemblage BIV in a single human isolate. All dog (n=3) and cat (n=2) isolates successfully genotyped were assigned to canine- and feline-specific assemblages C and F, respectively. No mixed assemblage or sub-assemblage infections could be demonstrated. Regarding Cryptosporidium, C. canis was found infecting dogs (n=2), and C. felis a single cat. Attempts to amplify and characterize Cryptosporidium human isolates failed repeatedly. Our results suggest that pet dogs and cats do not seem to play a significant role as suitable reservoirs of human giardiosis or cryptosporidiosis in the province of Álava. We conclude, therefore, that zoonotic transmission of giardiosis or cryptosporidiosis among pet dogs and cats and their owners in this geographical region is very likely a rare event.

Geospatial distribution of intestinal parasitic infections in Rio de Janeiro (Brazil) and its association with social determinants

BACKGROUND

Intestinal parasitic infections remain among the most common infectious diseases worldwide. This study aimed to estimate their prevalence and provide a detailed analysis of geographical distribution of intestinal parasites in the metropolitan region of Rio de Janeiro, considering demographic, socio-economic, and epidemiological contextual factors.

METHODS/PRINCIPAL FINDINGS

The cross-section survey was conducted among individuals attending the Evandro Chagas National Institute of Infectious Diseases (FIOCRUZ, RJ) during the period from April 2012 to February 2015. Stool samples were collected and processed by sedimentation, flotation, Kato-Katz, Baermann-Moraes and Graham methods, iron haematoxylin staining and safranin staining. Of the 3245 individuals analysed, 569 (17.5%) were infected with at least one parasite. The most common protozoa were Endolimax nana (28.8%), Entamoeba coli (14.8%), Complex Entamoeba histolytica/Entamoeba dispar (13.5%), Blastocystis hominis (12.7%), and Giardia lamblia (8.1%). Strongyloides stercoralis (4.3%), Schistosoma mansoni (3.3%), Ascaris lumbricoides (1.6%), and hookworms (1.5%) were the most frequent helminths. There was a high frequency of contamination by protozoa (87%), and multiple infections were observed in 141 participants (24.8%). A positive association between age (young children) and gender (male) with intestinal parasites was observed. Geospatial distribution of the detected intestinal parasitic infections was not random or homogeneous, but was influenced by socioeconomic conditions (through the material deprivation index (MDI)). Participants classified in the highest levels of deprivation had higher risk of having intestinal parasites.

CONCLUSIONS/SIGNIFICANCE

This study provides the first epidemiological information on the prevalence and distribution of intestinal parasitic infections in the Rio de Janeiro metropolitan area. Intestinal parasites, especially protozoa, are highly prevalent, indicating that parasitic infections are still a serious public health problem. MDI showed that intestinal parasites were strongly associated with the socioeconomic status of the population, thus making it possible to identify social vulnerable areas.

Microbial Indicators, Opportunistic Bacteria, and Pathogenic Protozoa for Monitoring Urban Wastewater Reused for Irrigation in the Proximity of a Megacity

In Latin America and the Caribbean, with a population of approximately 580 million inhabitants, less than 20 % of wastewater is treated. Megacities in this region face common challenges and problems related with water quality and sanitation, which require urgent actions, such as changes in the sustainable use of water resources. The Mexico City Metropolitan Area is one of the most populous urban agglomerations in the world, with over 20 million inhabitants, and is no exception to the challenges of sustainable water management. For more than 100 years, wastewater from Mexico City has been transported north to the Mezquital Valley, which is ranked as the largest wastewater-irrigated area in the world. In this study, bacteria and pathogenic protozoa were analyzed to determine the association between the presence of such microorganisms and water types (WTs) across sampling sites and seasons in Mexico City and the Mezquital Valley. Our results show a difference in microbiological water quality between sampling sites and WTs. There is no significant interaction between sampling sites and seasons in terms of bacterial concentration, demonstrating that water quality remains constant at each site regardless of whether it is the dry or the rainy season. The results illustrate the quantity of these microorganisms in wastewater, provide a current diagnosis of water quality across the area which could affect the health of residents in both Mexico City and the Mezquital Valley, and demonstrate the need to transition in the short term to treat wastewater from a local to a regional scale.

Prevalence of Cryptosporidium oocysts and Giardia cysts in raw and treated sewage sludges

Treated sludge from wastewater treatment plants (WWTPs) is commonly used in agriculture as fertilizers and to amend soils. The most significant health hazard for sewage sludge relates to the wide range of pathogenic microorganisms such as protozoa parasites.The objective of this study was to collect quantitative data on Cryptosporidium oocysts and Giardia cysts in the treated sludge in wastewater treatment facilities in Spain. Sludge from five WWTPs with different stabilization processes has been analysed for the presence of Cryptosporidium and Giardia in the raw sludge and after the sludge treatment. A composting plant (CP) has also been assessed. After a sedimentation step, sludge samples were processed and (oo)cysts were isolated by immunomagnetic separation (IMS) and detected by immunofluorescence assay (IFA). Results obtained in this study showed that Cryptosporidium oocysts and Giardia cysts were present in 26 of the 30 samples (86.6%) of raw sludge samples. In treated sludge samples, (oo)cysts have been observed in all WWTP's analysed (25 samples) with different stabilization treatment (83.3%). Only in samples from the CP no (oo)cysts were detected. This study provides evidence that (oo)cysts are present in sewage sludge-end products from wastewater treatment processes with the negative consequences for public health.

Modeling and kinetic characterization of wastewater disinfection using chlorine and UV irradiation

Sewage disinfection has the primary objective of inactivating pathogenic organisms to prevent the dissemination of waterborne diseases. This study analyzed individual disinfection, with chlorine alone, ultraviolet radiation alone, and a combined disinfection process (chlorine-UV radiation). Pseudomonas aeruginosa ATCC 15442, Escherichia coli ATCC 11229, Salmonella typhi ATCC 14028, and Clostridium perfringens were selected to evaluate the efficiency of different disinfection processes. The aim of the present study was to characterize the kinetics of chlorine (as NaHOCl) consumption, to evaluate responses of these bacterial species to the chlorination, the ultraviolet (UV) radiation, and the chlorine/UV disinfection processes in secondary wastewater using a batch laboratory reactor. Another target of this work was to study the modeling of the kinetic of water disinfection by chlorination and/or UV irradiation. Two kinetic models (Chick-Watson and Hom) were tested as to ability to scale disinfection of these bacterial species by different ultraviolet and/or chlorine doses. The results of the kinetics of chlorine consumption showed that monochloramines and trichloramines were the most important forms of residual chlorine as compared to free chlorine and dichloramines. The kinetics of inactivation of all examined bacterial strains showed that the application of the model of Hom in its original form was not representative of this kinetics of inactivation. Modification of this model, considering an initial decline of bacteria during the contact of water with chlorine, improved the results of the model. By the same, results revealed that the involved processes of UV irradiation were too complex to be approached by a simplified formulation, even in the case of specific strains of microorganisms and the use of nearly constant UV radiation intensity. In fact, the results have pointed out that the application of the Chick-Watson law is known to be inadequate to describe microbial inactivation with tailing or shoulder behavior. However, the UV kinetic studies also revealed that the first instants of exposure (2 to 10 s) to a UV intensity of 5 to 8 mW.cm-2 appeared as the deciding factors in disinfection with UV irradiation. It was shown that the combination of chlorine with UV yielded additive effects on the inactivation of bacterial strains and spectacular disinfection efficiency at a short contact time and less dose. In contrast to most studies, UV irradiation alone and chlorine alone exhibited low disinfection efficiency in inactivation of tested bacterial strains.

The Burden of Zoonoses in Kyrgyzstan: A Systematic Review

INTRODUCTION

Zoonotic disease (ZD) pose a serious threat to human health in low-income countries. In these countries the human burden of disease is often underestimated due to insufficient monitoring because of insufficient funding. Quantification of the impact of zoonoses helps in prioritizing healthcare needs. Kyrgyzstan is a poor, mountainous country with 48% of the population employed in agriculture and one third of the population living below the poverty line.

METHODOLOGY/PRINCIPAL FINDINGS

We have assessed the burden of zoonoses in Kyrgyzstan by conducting a systematic review. We have used the collected data to estimate the burden of ZDs and addressed the underestimation in officially reported disease incidence. The estimated incidences of the ZDs were used to calculate incidence-based Disability Adjusted Life Years (DALYs). This standardized health gap measure enhances comparability between injuries and diseases. The combined burden for alveolar echinococcosis, cystic echinococcosis, brucellosis, campylobacteriosis, congenital toxoplasmosis, non-typhoidal salmonellosis and rabies in Kyrgyzstan in 2013 was 35,209 DALYs [95% Uncertainty interval (UI):13,413-83,777]; 576 deaths [95% UI: 279-1,168] were attributed to these infections. We estimate a combined median incidence of ZDs of 141,583 cases [95% UI: 33,912-250,924] in 2013. The highest burden was caused by non-typhoidal Salmonella and Echinococcus multilocularis, respectively 14,792 DALYs [95% UI: 3,966-41,532] and 11,915 DALYs [95% UI: 4,705-27,114] per year.

CONCLUSION/SIGNIFICANCE

The health impact of zoonoses in Kyrgyzstan is substantial, comparable to that of HIV. Community-based surveillance studies and hospital-based registration of all occurrences of zoonoses would increase the accuracy of the estimates.

Prevalence of Entamoeba histolytica, Giardia lamblia, and Cryptosporidium spp. in Libya: 2000-2015

Introduction

The intestinal protozoa Entamoeba histolytica, Giardia lamblia, and Cryptosporidium spp. are the causative agents of giardiasis, amebiasis, and cryptosporidiosis, respectively. Adequate knowledge of the geographical distribution of parasites and the demographic variables that influence their prevalence is important for effective control of infection in at-risk populations.

Methods

The data were obtained by an English language literature search of Medline and PubMed for papers using the search terms ‘intestinal parasites and Libya, G. lamblia and Libya, E. histolytica and Libya and Cryptosporidium and Libya’ for the period 2000–2015.

Results

The data obtained for the period 2000–2015 showed prevalence rates of 0.8–36.6% (mean 19.9%) for E. histolytica/dispar, 1.2–18.2% (mean 4.6%) for G. lamblia and 0.9–13% (mean 3.4%) for Cryptosporidium spp. among individuals in Libya with gastroenteritis (GE). On the other hand, prevalence rates of 0.8–16.3% (mean 8.3%), 1.8–28.8% (mean 4.8%), and 1.0–2.5% (mean=2.4), respectively, were observed for individuals without GE. The mean prevalence rate of E. histolytica/dispar was significantly higher among individuals with GE compared with those without GE (p<0.0000001, OR=2.74). No significant difference in prevalence rate of the three organisms was found according to gender, but most of infections were observed in children aged 10 years or younger.

Conclusion

The reviewed data suggest that E. histolytica, G. lamblia, and Cryptosporidium spp. may play a minor role in GE in Libya. The observed high prevalence rates of E. histolytica/dispar reported from Libya could be due mainly to the non-pathogenic E. dispar and E. moshkovskii. However, more studies are needed in the future using E. histolytica-specific enzyme immunoassays and/or molecular methods to confirm this observation.

Prevalence of Cryptosporidium parvum/hominis, Entamoeba histolytica and Giardia lamblia among Young Children with and without Diarrhea in Dar es Salaam, Tanzania

Background

Although enteroparasites are common causes of diarrheal illness, few studies have been performed among children in Tanzania. This study aimed to investigate the prevalence of Cryptosporidium parvum/hominis, Entamoeba histolytica and Giardia lamblia among young children in Dar es Salaam, Tanzania, and identify risk factors for infection.

Methodology/Principal Findings

We performed an unmatched case-control study among children < 2 years of age in Dar es Salaam, recruited from August 2010 to July 2011. Detection and identification of protozoans were done by PCR techniques on DNA from stool specimens from 701 cases of children admitted due to diarrhea at the three study hospitals, and 558 controls of children with no history of diarrhea during the last month prior to enrollment. The prevalence of C. parvum/hominis was 10.4% (84.7% C. hominis), and that of G. lamblia 4.6%. E. histolytica was not detected. The prevalence of Cryptosporidium was significantly higher in cases (16.3%) than in controls (3.1%; P < 0.001; OR = 6.2; 95% CI: 3.7–10.4). G. lamblia was significantly more prevalent in controls (6.1%) than in cases (3.4%; P = 0.027; OR = 1.8; 95% CI: 1.1–3.1). Cryptosporidium infection was found more often in HIV-positive (24.2%) than in HIV-negative children (3.9%; P < 0.001; OR = 7.9; 95% CI: 3.1–20.5), and was also associated with rainfall (P < 0.001; OR = 2.41; 95% CI: 1.5–3.8). Among cases, stunted children had significantly higher risk of being infected with Cryptosporidium (P = 0.011; OR = 2.12; 95% CI: 1.2–3.8). G. lamblia infection was more prevalent in the cool season (P = 0.004; OR = 2.2; 95% CI: 1.3–3.8), and more frequent among cases aged > 12 months (P = 0.003; OR = 3.5; 95% CI: 1.5–7.8). Among children aged 7–12 months, those who were breastfed had lower prevalence of G. lamblia infection than those who had been weaned (P = 0.012).

Conclusions

Cryptosporidium infection is common among young Tanzanian children with diarrhea, particularly those living with HIV, and infection is more frequent during the rainy season. G. lamblia is frequently implicated in asymptomatic infections, but rarely causes overt diarrheal illness, and its prevalence increases with age.

Diarrheal diseases are a leading cause of disease and deaths among young children. In Africa they contribute to more than one tenth of childhood deaths. Parasites like Cryptosporidium, Entamoeba histolytica and Giardia lamblia are all common causes of diarrheal illness, but there are few studies on these enteroparasites among Tanzanian children. In this case-control study, we included 701 cases and 558 controls, all < 2 years of age, in Dar es Salaam, Tanzania. We assessed the prevalence of C. parvum/hominis, E. histolytica and G. lamblia by PCR, and the association with potential risk factors such as demographic data, clinical symptoms, HIV status and seasonality. One or more parasites were found in 14.9% of the samples. C. parvum/ hominis and G. lamblia were found in 10.4% and 4.6%, respectively, while E. histolytica was not found in any of the samples. The prevalence of Cryptosporidium was high, particularly in children with HIV, and its prevalence increased during the rainy season. Among cases, Cryptosporidium was found more frequently in stunted children, although any causal association could not be established in the current study. G. lamblia was more often implicated in asymptomatic infections than in overt diarrheal illness. The prevalence of G. lamblia increased with age, and breastfeeding seemed to protect the children from G. lamblia. This study presents relevant information about the prevalence and clinical characteristics of these intestinal parasites in Tanzanian children.