Effect of storage media, temperature, and time on preservation of Cryptosporidium parvum oocysts for PCR analysis

Isolation of phage-antibodies against Eimeria species that infect chickens

Eimeria is one of the most economically important pathogens in poultry production. Diagnosis of infection has the potential to inform treatment and prevention strategies. Here, phage display technology was used to isolate single chain antibodies (scFvs) that had a broad specificity against oocysts from the seven pathogenic species of Eimeria found in poultry. Three such scFvs, representing 2 scFv HCDR3 motifs, were isolated by random picks of clones isolated after five rounds of iterative enrichment (panning) of phage against the seven Eimeria species. Phage-antibody binding to Eimeria oocysts was also interrogated using next generation sequencing of the HCDR3 region of scFv genes contained with phage particles. This analysis demonstrated that the most abundant scFv found after 5 rounds of panning accounted for over >90 % of scFvs. Furthermore, the three scFvs isolated from random picks of clones were the only antibodies that were enriched through each round of panning. They were also seen to be enriched through the stages of phage panning that included binding to the Eimeria oocysts (selection phase) and to be selected against during the stages that consisted solely of phage propagation (growth only phase). The NGS data was further analysed to identify an additional scFv that demonstrated specific enrichment against 3 Eimeria species at the third round of panning and had the same pattern of enrichment during the selection and growth phases of panning. Rescue and analysis of this phage-scFv demonstrated a binder with broad specificity for Eimeria species. The four antibodies with broad specificity detected all seven Eimeria species in immunoassays. The binding of one such scFv that recognised all species was further validated by fluorescent microscopy.

Molecular detection of Cryptosporidium parvum in wild rodents (Phyllotis darwini) inhabiting protected and rural transitional areas in north-central Chile

Wild rodents often harbor Cryptosporidium species that can be transmitted to multiple mammal hosts. In Chile, little is known about Cryptosporidium in wild rodents, and available studies have been focused on morphological findings with no molecular-based evidence. A longitudinal survey was conducted between 2021 and 2022 to investigate the occurrence of Cryptosporidium spp. in populations of the Darwin's leaf-eared mouse (Phyllotis darwini) living in protected and rural transitional areas in north-central Chile, using staining and molecular methods. A total of 247 fecal samples were collected and examined by the modified Ziehl-Neelsen (ZN) staining test, 54 of which were positive for Cryptosporidium-like oocysts. Molecular analyses were carried out by PCR of the partial 18S ribosomal RNA and 60 kDa glycoprotein (gp60) genes. Cryptosporidium infection was confirmed in 34 samples (13.7 %) based on the PCR amplification, and individual (i.e., sex, and body mass index) and ecological variables (i.e., type of site and season) were not statistically significant (p > 0.05). Using the nucleotide sequencing of the partial 18S rRNA gene, Cryptosporidium parvum was identified in nine isolates. Also, C. parvum subgenotype family IIa was determined in seven samples by the partial gp60 gene, including the subtype IIaA17G4R1 in two samples. This is the first molecular evidence of Cryptosporidium parvum IIa in Phyllotis darwini in Chile. These results indicate potential cross-species transmition between wild rodents and domestic-wild animals in north-central Chile. More research is needed to understand better the role of wild rodents in the transmission of Cryptosporidium spp. in Chile.

Is Personal Protective Equipment Worth the Hassle? Annual Risk of Cryptosporidiosis to Dairy Farmers and How Personal Protective Equipment and Handwashing Can Mitigate It

Cows are known carriers of Cryptosporidium parvum (C. parvum), a protozoa that can cause the gastrointestinal illness cryptosporidiosis in humans. Despite this potential exposure, dairy farmers tend to wear personal protective equipment (PPE) to protect the milk from contamination, rather than to protect themselves from zoonotic diseases, such as cryptosporidiosis. In this study, cow feces were collected from individual cattle on dairy farms and analyzed for C. parvum using qPCR. Quantitative microbial risk assessment (QMRA) was used to determine the risk of cryptosporidiosis to the dairy farmer with and without the use of handwashing and PPE (gloves and masks). The annualized risk of cryptosporidiosis to dairy farmers was 29.08% but was reduced significantly in each of the three interventions. Among the individual interventions, glove use provided the greatest reduction in risk, bringing the annual risk of cryptosporidiosis to 4.82%. Implementing regular handwashing, the use of gloves and a mask brought the annual risk of cryptosporidiosis to 1.29%. This study provides evidence that handwashing and PPE use can significantly reduce the risk of cryptosporidiosis to farmers and is worth implementing despite potential barriers such as discomfort and cost.

Performance of sewage treatment technologies for the removal of Cryptosporidium sp. and Giardia sp.: Toward water circularity

Cryptosporidium sp. and Giardia sp. are parasites that cause diseases in the population. Most of parasite diseases regarding the consumption of drinking water polluted with sewage are caused by Cryptosporidium sp. or Giardia sp. it is because of the incomplete disinfection of the wastewater treatment. Therefore, in this work the removal or inactivation efficiency of different treatment technologies presented by around 40 scientific studies was evaluated, with a view to water circularity. For Cryptosporidium sp., we conclude that the most efficient secondary technologies are aerobic technologies, which remove between 0.00 and 2.17 log units (Ulog), with activated sludge presenting the greatest efficiency, and that the tertiary technologies with the greatest removal are those that use ultrasound, which reach removal values of 3.17 Ulog. In the case of Giardia sp., the secondary technologies with the greatest removal are anaerobic technologies, with values between 0.00 and 3.80 Ulog, and the tertiary technologies with the greatest removal are those that combine filtration with UV or a chemical disinfection agent. Despite the removal values obtained, the greatest concern remains detecting and quantifying the infectious forms of both parasites in effluents; therefore, although the technologies perform adequately, discharge effluents must be monitored with more sensitive techniques, above all aiming for circularity of the treated water in a context of the water scarcity that affects some parts of the world.

Well water sources simultaneous contamination with Cryptosporidium and Acanthamoeba in East-Southeast Asia and Acanthamoeba spp. in biofilms in the Philippines

Cryptosporidium is the leading agent of waterborne parasitic protozoan outbreaks and is the second leading cause of infant mortality due to diarrhoea worldwide. Acanthamoeba spp. causes Acanthamoeba keratitis (AK) and a life-threatening condition known as granulomatous amoebic encephalitis (GAE). The present study aimed to assess the water quality of an indigenous and a rural community for waterborne parasitic protozoan contamination. Aquatic samples (n = 22) were processed by filtration of 500 mL portion through a 1.2 μm pore size glass microfiber filter and eluted for light microscopy, culture in non-nutrient agar, and PCR analysis. Overall, 36% (8/22) of the investigated aquatic samples were positive for either Cryptosporidium spp. oocysts (13%; 3/22) or Acanthamoeba spp., (36%; 8/22) or both (13%; 3/22). Cryptosporidium spp. oocysts were detected in 27% (3/11) of wet season samples only while Acanthamoeba spp. were detected in 18% (2/11) and 55% (6/11) of wet and dry season samples, respectively. Subsequently, molecular detection for Acanthamoeba species identified A. lenticulata and A. hatchetti with 98-99% BLAST similarity. This is the first report on the simultaneous contamination of Cryptosporidium and Acanthamoeba in well water sources in East-Southeast Asia, the first detection of Acanthamoeba spp. in biofilms in the Philippines, and the longest viability demonstrated for A. lenticulata in two-year-old water samples stored at room temperature.

Prevalence and Molecular Epidemiology of Cryptosporidium Infection in Clarias gariepinus Fish in Egypt

PURPOSE

This study investigated the prevalence and molecular detection of Cryptosporidium spp. in catfish (Clarias gariepinus).

METHODS

A total of 300 Carias gariepinus fish were collected from two freshwater sources: the Nile River (180) and drainage canals (120). The stomach and intestine epithelium of each individual fish sample were screened by modified Ziehl-Neelsen (mZN) staining technique for the detection of Cryptosporidium oocysts followed by the serological survey for detection of Cryptosporidium antibodies using Enzyme-Linked Immunosorbent Assay (ELISA) and molecular characterization using complemented DNA polymerase chain reaction (cPCR).

RESULTS

ELISA showed higher prevalence of 69.3% than that prevalence obtained by mZN, 64% for the total examined Clarias gariepinus fish. Also, higher prevalence of Cryptosporidium infection 65.5% and 75.8% obtained by ELISA than 61.1% and 68.3% by mZN, in both fish groups from Nile River and Drainage canal, respectively. PCR analysis revealed the expected positive bands at 1056 bp. DNA sequencing and phylogenetic analysis proved that the positive-PCR Cryptosporidium isolate identified in the present study was Cryptosporidium molnari.

CONCLUSION

Freshwater fishes (Clarias gariepinus) are subjected to a high infection rate with Cryptosporidium spp.; the drainage canals obtained fishes showed higher prevalence than that collected from Nile River which indicates an important public health problem and a potential risk of drainage canals in Egypt. ELISA showed higher prevalence of cryptosporidiosis than mZN, for the total examined Clarias gariepinus fish and phylogenetic analyses confirmed this protozoal organism to be a novel species of Cryptosporidium molnari.

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.

Detection of Zoonotic Cryptosporidium ubiquitum in Alpine Wild Ruminants

Cryptosporidium is a widespread apicomplexan protozoan of major zoonotic importance, characterized by a wide host range, and with relevant economic implications and potential negative effects on livestock and wildlife population dynamics. Considering the recent strong demographic increase of alpine ungulates, in this study, carried out in the Italian Northwestern Alps, we investigated the occurrence of Cryptosporidium spp. in these species and their potential involvement in environmental contamination with Cryptosporidium spp. oocysts. The immune-enzymatic approach revealed a Cryptosporidium prevalence of 1.7% (5/293), 0.5% (1/196) and 3.4% (4/119) in alpine chamois (Rupicapra rupicapra), red deer (Cervus elaphus) and roe deer (Capreolus capreolus), respectively. Positive samples were subjected to polymerase chain reaction (PCR) amplification for the COWP and gp60 genes. The presence of Cryptosporidium was confirmed in one chamois and four roe deer. Sequences obtained clustered within Cryptosporidium&nbsp;ubiquitum, currently recognized as an emerging zoonotic species. This finding represents the first detection of zoonotic C.&nbsp;ubiquitum in chamois and in the Alpine environment. Despite the low observed prevalences, environmental contamination by oocysts could play a role as a potential source of infections for humans and livestock.

Molecular epidemiology of Cryptosporidium spp. in an agricultural area of northern Vietnam: A community survey

The purpose of this study was to investigate the occurrence of Cryptosporidium infection and the potential for transmission of Cryptosporidium spp. between animals and humans in northern Vietnam. A total of 2715 samples (2120 human diarrheal samples, 471 human non-diarrheal samples, and 124 animal stool samples) were collected through our community survey in an agricultural area. All samples were tested for Cryptosporidium spp. by direct immunofluorescence assay (DFA) using a fluorescent microscope. DNA extraction, PCR amplification of three genes (COWP, SSU-rRNA, and GP60), and sequencing analysis were performed to identify Cryptosporidium spp. Of 2715 samples, 15 samples (10 diarrheal samples, 2 non-diarrheal samples, and 3 animal stool samples) tested positive by PCR for the COWP gene. Three species of Cryptosporidium spp. were identified as C. canis (from six human diarrheal samples, two human non-diarrheal samples, and one dog sample), C. hominis (from four human diarrheal samples), and C. suis (from two pig samples) by sequencing the amplified COWP and/or SSU-rRNA genes. In terms of C. hominis, the GP60 subtype IeA12G3T3 was detected in all four human diarrheal samples. Although the number of positive samples was very small, our epidemiological data showed that the emerging pattern of each of the three species (C. canis, C. hominis, and C. suis) was different at this study site. While C. hominis and C. suis were only detected in human and pig samples, respectively, C. canis was detected in samples from both dogs and humans. We suspect that C. canis infections in humans at this study site may be due to environmental contamination with animal and human feces.

Comparison of current methods used to detect Cryptosporidium oocysts in stools

In this review all of the methods that are currently in use for the investigation of Cryptosporidium in stool material are highlighted and critically discussed. It appears that more qualifications and background knowledge in this field regarding the diagnosis of the Cryptosporidium parasite is required. Furthermore, there is no standardization for the protocols that are commonly used to either detect oocysts in faeces or to diagnose the Cryptosporidium infection. It is therefore necessary to initiate further education and research that will assist in improving the accuracy of the diagnosis of Cryptosporidium oocysts in the faecal micro-cosmos. Where ambient concentrations of oocysts are low in stool material, detection becomes a formidable task. Procedures for ring tests and the standardization of multi-laboratory testing are recommended. It is also necessary to enhance the routine surveillance capacity of cryptosporidiosis and to improve the safety against it, considering the fact that this disease is under diagnosed and under reported. This review is intended to stimulate research that could lead to future improvements and further developments in monitoring the diagnostic methodologies that will assist in harmonizing Cryptosporidium oocysts in stool diagnosis.

Cryptosporidium spp. and Giardia spp. in feces and water and the associated exposure factors on dairy farms

The aims of this study were to verify the prevalence of Cryptosporidium spp. and Giardia spp. in animal feces and drinking water on dairy farms and to identify a possible relation between the exposure factors and the presence of these parasites. Fecal samples from cattle and humans and water samples were collected on dairy farms in Paraná, Brazil. Analysis of (oo)cysts in the feces was performed by the modified Ziehl-Neelsen staining and centrifugal flotation in zinc sulfate. Test-positive samples were subjected to nested PCR amplification of the 18SSU ribosomal RNA gene for identification of Cryptosporidium and Giardia and of the gp60 gene for subtyping of Cryptosporidium. Microbiological analysis of water was carried out by the multiple-tube method and by means of a chromogenic substrate, and parasitological analysis was performed on 31 samples by direct immunofluorescence and nested PCR of the genes mentioned above. Identification of the species of Cryptosporidium was performed by sequencing and PCR with analysis of restriction fragment length polymorphisms. The prevalence of Giardia and Cryptosporidium was higher in calves than in adults. Among the samples of cattle feces, Cryptosporidium parvum was identified in 41 (64%), C. ryanae in eight (12.5%), C. bovis in four (6.3%), C. andersoni in five (7.8%), and a mixed infection in 20 samples (31.3%). These parasites were not identified in the samples of human feces. Thermotolerant coliform bacteria were identified in 25 samples of water (45.5%). Giardia duodenalis and C. parvum were identified in three water samples. The gp60 gene analysis of C. parvum isolates revealed the presence of two strains (IIaA20G1R1 and IIaA17G2R2) in the fecal samples and one (IIaA17G2R1) in the water samples. The presence of coliforms was associated with the water source, structure and degradation of springs, rain, and turbidity. The prevalence of protozoa was higher in calves up to six months of age. C. parvum and G. duodenalis were identified in the water of dairy farms, as were thermotolerant coliforms; these findings point to the need for guidance on handling of animals, preservation of water sources, and water treatment.

A cluster-randomised controlled trial integrating a community-based water, sanitation and hygiene programme, with mass distribution of albendazole to reduce intestinal parasites in Timor-Leste: the WASH for WORMS research protocol

INTRODUCTION

There is limited evidence demonstrating the benefits of community-based water, sanitation and hygiene (WASH) programmes on infections with soil-transmitted helminths (STH) and intestinal protozoa. Our study aims to contribute to that evidence base by investigating the effectiveness of combining two complementary approaches for control of STH: periodic mass administration of albendazole, and delivery of a community-based WASH programme.

METHODS AND ANALYSIS

WASH for WORMS is a cluster-randomised controlled trial to test the hypothesis that a community-based WASH intervention integrated with periodic mass distribution of albendazole will be more effective in reducing infections with STH and protozoa than mass deworming alone. All 18 participating rural communities in Timor-Leste receive mass chemotherapy every 6 months. Half the communities also receive the community-based WASH programme. Primary outcomes are the cumulative incidence of infection with STH. Secondary outcomes include the prevalence of protozoa; intensity of infection with STH; as well as morbidity indicators (anaemia, stunting and wasting). Each of the trial outcomes will be compared between control and intervention communities. End points will be measured 2 years after the first albendazole distribution; and midpoints are measured at 6 months intervals (12 months for haemoglobin and anthropometric indexes). Mixed-methods research will also be conducted in order to identify barriers and enablers associated with the acceptability and uptake of the WASH programme.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the human ethics committees at the University of Queensland, Australian National University, Timorese Ministry of Health, and University of Melbourne. The results of the trial will be published in peer-reviewed journals presented at national and international conferences, and disseminated to relevant stakeholders in health and WASH programmes. This study is funded by a Partnership for Better Health--Project grant from the National Health and Research Council (NHMRC), Australia.

TRIAL REGISTRATION NUMBER

ACTRN12614000680662; Pre-results.

An evaluation of the potential use of Cryptosporidium species as agents for deliberate release

INTRODUCTION

We evaluated the potential of Cryptosporidium spp. for intentional transmission as a terrorist tactic in asymmetric conflicts in terms of the recognised optimum conditions for biological warfare.

METHODS

Published and widely accepted criteria regarding the optimum conditions for the success of biological warfare based on experience from passive biological warfare research were applied to hypothetical intentional Cryptosporidium spp. transmission.

RESULT

The feasibility of the use of Cryptosporidium spp. transmission for terrorist purposes was established. Particularly on tropical deployments with poor hygiene conditions, such attacks might have a good chance of remaining undetected as a deliberate terrorist attack.

CONCLUSIONS

Intentional transmission should be suspected in cases of sudden outbreaks of cryptosporidiosis, particularly where adequate food and drinking water hygiene precautions are being enforced. Appropriate diagnostic procedures should be available so that the diagnosis is not missed.