Synanthropic flies as vectors of Cryptosporidium and Giardia among livestock and wildlife in a multispecies agricultural complex

Evaluating the role of synanthropic filth flies in the transmission of zoonotic parasites: field and laboratory evidence from different animal rearing sites in upper Egypt with focus on Cryptosporidium spp

BACKGROUND

Synanthropic filth flies thrive in human and animal habitats, posing health risks through the transmission of infectious agents. They breed on organic waste, including animal feces, making them carriers of various pathogens. In Egypt, where livestock farming is common and poor sanitation, these flies may contribute to zoonotic disease transmission. The current study investigates parasitic infections in filth flies from three livestock farms in Assiut Governorate, Upper Egypt, highlighting their role as vectors for zoonotic infections, particularly Cryptosporidium, via morphological and molecular tools.

METHODS

A total of 12,749 flies were collected from the study sites via sweep nets. After taxonomic identification, the flies were examined microscopically for parasites using various concentration and staining techniques. Positive samples were further confirmed for infections, particularly for Cryptosporidium parasites, via nested PCR and sequence analysis targeting the COWP and SSU rRNA genes.

RESULTS

This study revealed the presence of several fly species from seven dipteran families, particularly the family Muscidae, primarily Musca domestica, which presented a high parasite infestation rate of 96.6%. This study revealed a high prevalence of various protozoans and helminths in the collected flies. Cryptosporidium was the most prevalent parasite (64.4-100%), infecting all fly species. Entamoeba and Balantidium were also significant, especially in M. domestica (22.6-90.1%, 8.9-100%), Fannia canicularis (10.5-74.4%, 44.2-88.2%), and Borborillus vitripennis (11.1-50%, 37.2-91.4%). Giardia, Trichuris, and Trichostrongylidae had low to moderate prevalence in multiple fly species. Mites are commonly detected on fly exoskeletons, with high infestation rates observed in Musca domestica (77-100%) and Physiphora alceae (66.7-100%). The present study also reported sporadic infections with Trichomonas, Toxocara vitulorum, and pseudoscorpions, along with notable midge larval infestations (52.1%), mainly at site B. Parasitic infections were highest in autumn and spring, with the lowest rates in winter. Molecular identification confirmed the presence of the zoonotic species Cryptosporidium parvum and Cladotanytarsus gedanicus.

CONCLUSION

This study revealed that zoonotic parasites exist in flies and pose potential risks when they are found near humans. Cryptosporidium parvum is the prevalent parasite causing diarrhea outbreaks in animals. This is the first genetic evidence of Cladotanytarsus gedanicus midge from Upper Egypt.

Flies as Carriers of Gastrointestinal Protozoa of Interest in Public Health in the Northeast of Brazil

PURPOUSE

This study aimed to assess the influence of the presence of synanthropic flies in food preparation environments on the transmission of potentially zoonotic gastrointestinal protozoa.

METHODS

Flies were captured using a glass containing water, fruits, and pieces of protein.

RESULTS

Approximately 260 flies from four different species were captured: Musca domestica (76.92%; 200/260), Cochliomyia hominivorax (17.31%; 45/260), Lucilia cuprina (3.85%; 10/260), and Hydrotaea aenescens (1.92%; 5/260). Protozoa were identified through microscopic analysis after macerating these arthropods contained in their respective eppendorfs, using two techniques, namely Mini-FLOTAC® and centrifugal sedimentation with Ziehl-Neelsen staining. The analysis revealed a concerning scenario regarding the epidemiological chain of gastrointestinal protozoa in Sergipe, Northeast Brazil. The positivity rate was 26.92% (14/52) of the pools, with 100.00% (5/5) in Aracaju, 30.00% (3/10) in Nossa Senhora do Socorro, 27.27% (3/11) in Nossa Senhora da Glória, 12.50% (2/16) in Carmópolis, and 10.00% (1/10) in Nossa Senhora das Dores. Two species of protozoa were identified, namely Cryptosporidium spp. (23.08%; 12/52) and Entamoeba spp. (9.62%; 5/52). The involvement of two fly species in the maintenance of the life cycle of these protozoa was noticeable, specifically M. domestica (27.50%; 11/40) and C. hominivorax (22.22%; 2/9).

CONCLUSIONS

Counties analyzed had an human development index (HDI) considered medium; however, they still faced socioeconomic problems such as absence of sanitation systems, waste accumulation in the streets, and illegal waste disposal, which could favor the proliferation of these vectors and the spread of these gastrointestinal protozoa.

Prevalence and associated risk factors of Cryptosporidium infection in calves and hospitalized humans in Libo Kemkem, North Western Ethiopia

BACKGROUND

Cryptosporidium infection is one of the major causes of acute gastroenteritis and diarrhoea caused by a protozoan parasite affecting vertebrates and humans. The disease is prevalent in cases of immunocompromised individuals. Despite the impact of the diseases in calf and hospitalized humans, well-documented studies are not available in the study area.

OBJECTIVES

The objectives of this study were to determine the prevalence of Cryptosporidium infection in calves and hospitalized humans and assess the major associated risk factors associated with Cryptosporidium infection in calves and hospitalized humans.

METHOD

A cross-sectional study was conducted from November 2020 to March 2021 on calf and human Cryptosporidium infection in Libo Kemkem District, North West Ethiopia. A total of 193 calves and 122 human stool samples admitted to the hospital were used for this study. Three kebeles were selected purposely, and individual calves were selected using a simple random sampling method. A number of sampled calves were allocated proportionally to the selected kebeles. Human samples were collected using a systematic random sampling method. Faecal and stool samples were examined using a modified Ziehl-Neelsen staining method.

RESULT

The overall prevalence of calf and human Cryptosporidium infection found in this study was 15.5% and 11.5%, respectively. Age of calf, breed, body condition, water source, faecal consistency and hygienic condition were found significantly (p < 0.05) associated with Cryptosporidium infection in the calf. Similarly, the source of potable water, immunocompromisation and contact with domestic animals were found to be significantly (p < 0.05) associated with Cryptosporidium infection in humans.

CONCLUSION

There was a higher prevalence of Cryptosporidium infection in calves and humans in Libo Kemkem District. Therefore, the implementation of proper prevention methods of zoonotic Cryptosporidium infection between calf and human beings through significant risk factors is mandatory. Furthermore, additional studies to investigate the levels of economic importance of the disease should be conducted.

Investigating the relationship between extreme weather and cryptosporidiosis and giardiasis in Colorado: A multi-decade study using distributed-lag nonlinear models

Environmentally-mediated protozoan diseases like cryptosporidiosis and giardiasis are likely to be highly impacted by extreme weather, as climate-related conditions like temperature and precipitation have been linked to their survival, distribution, and overall transmission success. Our aim was to investigate the relationship between extreme temperature and precipitation and cryptosporidiosis and giardiasis infection using monthly weather data and case reports from Colorado counties over a twenty-one year period. Data on reportable diseases and weather among Colorado counties were collected using the Colorado Electronic Disease Reporting System (CEDRS) and the Daily Surface Weather and Climatological Summaries (Daymet) Version 3 dataset, respectively. We used a conditional Poisson distributed-lag nonlinear modeling approach to estimate the lagged association (between 0 and 12-months) between relative temperature and precipitation extremes and the risk of cryptosporidiosis and giardiasis infection in Colorado counties between 1997 and 2017, relative to the risk found at average values of temperature and precipitation for a given county and month. We found distinctly different patterns in the associations between temperature extremes and cryptosporidiosis, versus temperature extremes and giardiasis. When maximum or minimum temperatures were high (90th percentile) or very high (95th percentile), we found a significant increase in cryptosporidiosis risk, but a significant decrease in giardiasis risk, relative to risk at the county and calendar-month mean. Conversely, we found very similar relationships between precipitation extremes and both cryptosporidiosis and giardiasis, which highlighted the prominent role of long-term (>8 months) lags. Our study presents novel insights on the influence that extreme temperature and precipitation can have on parasitic disease transmission in real-world settings. Additionally, we present preliminary evidence that the standard lag periods that are typically used in epidemiological studies to assess the impacts of extreme weather on cryptosporidiosis and giardiasis may not be capturing the entire relevant period.

Minimal zoonotic risk of cryptosporidiosis and giardiasis from frogs and reptiles

The zoonotic potential of the protist parasites Cryptosporidium spp. and Giardia duodenalis in amphibians and reptiles raises public health concerns due to their growing popularity as pets. This review examines the prevalence and diversity of these parasites in wild and captive amphibians and reptiles to better understand the zoonotic risk. Research on Giardia in both groups is limited, and zoonotic forms of Cryptosporidium or Giardia have not been reported in amphibians. Host-adapted Cryptosporidium species dominate in reptiles, albeit some reptiles have been found to carry zoonotic (C. hominis and C. parvum) and rodent-associated (C. tyzzeri, C. muris and C. andersoni) species, primarily through mechanical carriage. Similarly, the limited reports of Giardia duodenalis (assemblages A, B and E) in reptiles may also be due to mechanical carriage. Thus, the available evidence indicates minimal zoonotic risk associated with these organisms in wild and captive frogs and reptiles. The exact transmission routes for these infections within reptile populations remain poorly understood, particularly regarding the importance of mechanical carriage. Although the risk appears minimal, continued research and surveillance efforts are necessary to gain a more comprehensive understanding of the transmission dynamics and ultimately improve our ability to safeguard human and animal health.

Study on genetic characteristics of Cryptosporidium isolates and first report of C. parvum IIdA24G2 subtype in dairy cattle in China

Cryptosporidium is an important gastrointestinal parasite that can cause mild to severe diarrhea in various vertebrates, including humans and domestic animals. Infection is prevalent in dairy cattle, particularly calves, resulting in diarrhea and increased mortality with significant production losses. However, the prevalence and identity of Cryptosporidium spp. in cattle in Heilongjiang Province is still poorly known. Our study aimed to investigate the prevalence and species and subtype distribution of Cryptosporidium in cattle in the region. In addition, we evaluated the zoonotic potential of Cryptosporidium isolates and assessed possible transmission routes and health effects of this organism. We collected 909 fecal samples from five different farms in Heilongjiang Province between August and September 2022. The samples underwent Cryptosporidium detection by nested PCR and small subunit (SSU) rRNA gene sequence analysis. Four Cryptosporidium species were identified, including C. parvum, C. bovis, C. ryanae, and C. andersoni, with an overall prevalence of 4.4% (40/909). Based on sequence analysis of the 60 kDa glycoprotein gene of C. parvum and C. bovis, three subtypes of C. parvum were identified, namely two previously known subtypes (IIdA19G1 and IIdA20G1), and one novel subtype (IIdA24G2). Two distinct subtype families were identified in C. bovis (XXVId and XXVIe). The high diversity of Cryptosporidium in dairy cattle and the emergence of a novel subtype of C. parvum in Heilongjiang Province suggest that dairy cattle may serve as a significant source of zoonotic cryptosporidiosis infection in this region.

Aphaereta pallipes (Hymenoptera: Braconidae) and Dirhinus anthracia (Hymenoptera: Chalcididae) associated with Peckia (Euboettcheria) collusor (Diptera: Sarcophagidae) in Brazil

Flies of the Sarcophagidae family are widely distributed in the world, occupying different habitats. Some species have a high degree of synanthropy and are therefore often found in households in the urban environment. In Brazil, there is still little information related to the natural enemies of these insects in the urban environment, where population control is strictly chemical. Therefore, larvae and pupae of Peckia (Euboettcheria) collusor (Curran and Walley) (Diptera: Sarcophagidae) species were exposed in an urbanized location, and the presence and prevalence of parasitoids in the natural control of these immature stages was evaluated. We report for the first time the species Aphaereta pallipes (Say) (Hymenoptera: Braconidae) and Dirhinus anthracia Walker (Hymenoptera: Chalcididae), associated with P. (E.) collusor, highlighting the importance of these parasitoids in natural control in the urban environment, in addition to expanding the list of hosts for both parasitoid species and the distribution of this parasitoid-host interaction for Brazil and the Neotropical region.

Snakes and Souks: Zoonotic pathogens associated to reptiles in the Marrakech markets, Morocco

The world-famous markets of Marrakech, also known in Arabic as souks, harbor a vast diversity of reptiles that are sold for medicinal/magic/pet purposes or used for snake charming. This unique epidemiological context has never been studied considering the interactions of humans, reptiles, and zoonotic pathogens. Thus, the aim of this study was to identify the parasites and pathogens present in blood and feces associated with handled reptiles in the markets of Marrakech to assess the risk of zoonotic transmission within the reptile-human interface. Privately owned reptiles (n = 118), coming from vendors or snake charmers, were examined and blood and feces sampled. DNA was extracted and molecular screening (cPCR, nPCR, qPCR, dqPCR) was performed aiming to identify potentially zoonotic pathogens (i.e., Anaplasma/Ehrlichia spp., Rickettsia spp., Borrelia burgdorferi sensu lato, Coxiella burnetii, Babesia/Theileria spp., Cryptosporidium spp., Giardia spp., Leishmania spp., Cestoda). Overall, 28.9% (34/118) of reptiles were positive for at least one pathogen. In blood, Anaplasma spp. were detected in four snakes, with two Montpellier snakes positive for Anaplasma phagocytophilum, while Rickettsia spp. were detected in one Mediterranean chameleon and four puff adders. Leishmania tarentolae was molecularly detected in a Mediterranean chameleon and a Montpellier snake. In feces, the cox1 gene generated a myriad of sequences for nematodes, cestodes, fungi and bacteria. Importantly, Proteus vulgaris was identified from a Mediterranean chameleon. Cryptosporidium spp. nPCR yielded a positive sample (i.e., Cryptosporidium sp. apodemus genotype I) from a Moroccan worm lizard, as well as for bacteria such as Pseudomonas aeruginosa in an Egyptian cobra, and Morganella morganii from a puff adder. Results from this study demonstrated the risk of zoonotic transmission of microorganisms and parasites present in blood and feces from reptiles that are brought to the souks in Marrakech, Morocco, to be sold for medicinal purposes or used for snake charming, being in direct and straight contact with humans.

Relevant Brachycera (Excluding Oestroidea) for Horses in Veterinary Medicine: A Systematic Review

In equine stables and their surroundings, a large number of insects are present that can be a nuisance to their equine hosts. Previous studies about dipterans transmitting infectious agents to Equidae have largely focused on Nematocera. For the preparation of this systematic review, the existing literature (until February 2022) was systematically screened for various infectious agents transmitted to Equidae via insects of the suborder Brachycera, including Tabanidae, Muscidae, Glossinidae and Hippoboscidae, acting as pests or potential vectors. The PRISMA statement 2020 (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for systematic reviews were followed. The two concepts, Brachycera and Equidae, were combined for the search that was carried out in three languages (English, German and French) using four different search engines. In total, 38 articles investigating Brachycera as vectors for viral, bacterial and parasitic infections or as pests of equids were identified. Only 7 of the 14 investigated pathogens in the 38 reports extracted from the literature were shown to be transmitted by Brachycera. This review clearly shows that further studies are needed to investigate the role of Brachycera as vectors for pathogens relevant to equine health.

Cryptosporidiosis in Finland is predominantly of domestic origin: investigation of increased reporting, 1995-2020

BACKGROUND

Cryptosporidiosis is gastroenteritis caused by Cryptosporidium. Since 2017, reporting of cryptosporidiosis has increased in Finland.

METHODS

We describe demographics of cryptosporidiosis cases notified to Finnish Infectious Disease Register (FIDR) during a 21-year surveillance period, 1995-2020, and a retrospective investigation of increased cryptosporidiosis in Ostrobothnian hospital districts in summer 2018.

RESULTS

Incidence of cryptosporidiosis during the period 2017-2020 represented 20-fold increase from the period 1995-2016, with the highest incidence detected in Ostrobothnia. In 2018, cryptosporidiosis in Ostrobothnia was associated with living on or visiting a farm where the production animals had diarrhoea, noticing more flies than usual, gardening or handling manure and having a family member with gastroenteritis. Four gp60 subtypes were identified in patient samples: IIaA18G1R1, IIaA15G2R1, IIaA13G2R1 and IIaA15G1R1.

CONCLUSIONS

In Finland, Cryptosporidium has been included in gastrointestinal PCR diagnostic panels in most clinical laboratories since 2016. Since then, the number of reported cases has subsequently increased, indicating improved diagnostics and awareness of the illness. In 2018, several C. parvum subtypes were identified in patients suggesting that the increase was not caused by a single source. Cryptosporidiosis increased in Finland in 2020 despite hand washing recommendations and travel restrictions imposed during the COVID-19 pandemic, indicating that domestic cases are more frequent than previously considered. To monitor cause and origin of cryptosporidiosis and the effect of control measures, Cryptosporidium should be identified at subspecies level, and travel history should be included in FIDR notification. Those working with cattle and calves require precise instructions on how to prevent C. parvum infection.

The global prevalence of parasites in non-biting flies as vectors: a systematic review and meta-analysis

BACKGROUND

Non-biting flies such as the house fly (Musca domestica), the Australian sheep blowfly (Lucilia cuprina) and the oriental latrine fly (Chrysomya megacephala) may carry many parasites. In the present study, we performed a systematic overview of the different species of parasites carried by non-biting flies, as well as of isolation methods, different geographical distribution, seasonality and risk assessment.

METHODS

A meta-analysis was carried out with the aim to review the global prevalence of parasite transmission in non-biting flies. A total sample size of 28,718 non-biting flies reported in studies worldwide satisfied the predetermined selection criteria and was included in the quantitative analysis.

RESULTS

The global prevalence of parasites in non-biting flies was 42.5% (95% confidence interval [CI] 31.9-53.2%; n = 15,888/28,718), with the highest prevalence found for non-biting flies in Africa (58.3%; 95% CI 47.4-69.3%; n = 9144/13,366). A total of 43% (95% CI 32.1-54.4%; n = 7234/15,282) of house flies (M. domestica), the fly species considered to be the most closely associated with humans and animals, were found with parasites. The prevalence of parasites in the intestine of non-biting flies was 37.1% (95% CI 22.7-51.5%; n = 1045/3817), which was significantly higher than the prevalence of parasites isolated from the body surface (35.1%; 95% CI 20.8-49.4%; n = 1199/3649; P < 0.01). Of the 27 reported parasites, a total of 20 known zoonotic parasites were identified, with an infection rate of 38.1% (95% CI 28.2-48.0%; n = 13,572/28,494).

CONCLUSIONS

This study provides a theoretical basis for the public health and ecological significance of parasites transmitted by non-biting flies.

Molecular identification of Cryptosporidium species from domestic ruminants and wild reptiles in Cyprus

The presence of Cryptosporidium species in faecal samples of 32 sheep (Aries bovis), 10 goats (Capra circus), 1 blunt nose viper (Macrovipera lebetina lebetina), 3 Kotschy’s geckos (Mediodactylus kotschyi) and 6 wild stellagamas (Stellagama stellio cypriaca) in Cyprus were investigated by polymerase chain reaction (PCR) and sequencing. Cryptosporidium species were found in 9/32 sheep, 5/10 goats, 2/3 Kotschy’s geckos and 2/6 stellagamas faecal samples based on the sequencing of the 18S rRNA gene. Subtyping was achieved based on the sequencing of the gp60 gene. Four different species have been identified: Cryptosporidium parvum in goats (subtype IIaA15G1R1), C. xiaoi (subtypes XXIIId and XXIIIl) and C. ubiquitum (subtype XIIa) in sheep and C. varanii and C. parvum in lizards; the viper snake sample was negative. This is the first report on the molecular identification of a variety of Cryptosporidium species from domestic ruminants and wild reptiles in the Republic of Cyprus.

Giardia intestinalis and its Endomembrane System

Giardia intestinalis has unique characteristics, even in the absence of certain organelles. For instance, Golgi and mitochondria are not found. On the other hand, there is a network of peripheral vacuoles (PVs) and mitosomes. The endoplasmic reticulum (ER), nuclear membrane, peroxisomes, and lipid bodies are present. The peripheral vacuole system seems to play several simultaneous roles. It is involved in the endocytic activity of the trophozoite but also has characteristics of early and late endosomes and even lysosomes, establishing a connection with the ER. Some of the PVs contain small vesicles, acting as multivesicular bodies, including the release of exosomes. The mitosomes are surrounded by two membranes, divide during mitosis, and are distributed throughout the cell. They do not contain DNA, enzymes involved in the citric acid cycle, respiratory chain, or ATP synthesis. However, they contain the iron-sulfur complex and transporters as TOM and TIM. Some mitosomes are linked to flagellar axonemes through a fibrillar connection. During encystation, two types of larger cytoplasmic vesicles appear. One originating from the ER contains the cyst wall proteins. Another contains carbohydrates. Both migrate to the cell periphery and fuse with plasma membrane secreting their contents to give rise to the cell wall.

A Systematic Review of Zoonotic Enteric Parasites Carried by Flies, Cockroaches, and Dung Beetles

Filth flies, cockroaches, and dung beetles have been close neighbors with humans and animals throughout our joint histories. However, these insects can also serve as vectors for many zoonotic enteric parasites (ZEPs). Zoonoses by ZEPs remain a paramount public health threat due to our close contact with animals, combined with poor water, sanitation, and hygiene access, services, and behaviors in many global regions. Our objective in this systematic review was to determine which ZEPs have been documented in these vectors, to identify risk factors associated with their transmission, and to provide effectual One Health recommendations for curbing their spread. Using PRISMA guidelines, a total of 85 articles published from 1926 to 2021 were reviewed and included in this study. Qualitative analysis revealed that the most common parasites associated with these insects included, but were not limited to: Ascaris spp., Trichuris spp., Entamoeba spp., and Cryptosporidium spp. Additionally, prominent risk factors discovered in the review, such as poor household and community WASH services, unsafe food handling, and exposure to domestic animals and wildlife, significantly increase parasitic transmission and zoonoses. The risk of insect vector transmission in our shared environments makes it critically important to implement a One Health approach in reducing ZEP transmission.

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.

Synanthropy of Sarcophaginae (Diptera: Sarcophagidae) From Southern Brazil and Its Sanitary Implications

Although different feeding habits have been reported for Sarcophaginae (Diptera, Sarcophagidae), most species are associated with decomposing organic matter such as feces and decaying corpses. This study provides the synanthropy index for males of species of Sarcophaginae collected during a 12-mo period in three different environments (urban, rural, and wild) of the state of Rio Grande do Sul, in Southern Brazil, linking this parameter with the sanitary issue. This article also investigated the presence of pathogenic bacteria on the external surface of Oxysarcodexia paulistanensis (Mattos), the most abundant species collected using a sanitized entomological net. Almost all the species collected most abundantly, including O. paulistanensis (n = 241), Ravinia advena (Walker) (n = 87), and O. thornax (Walker) (n = 58), were classified as synanthropic; O. thornax was the species with the highest synanthropy index (+80.3). Escherichia coli (Escherich), Shigella spp. (Enterobacteriaceae), and Staphylococcus aureus (Rosenbach) (Staphylococcaceae) were isolated and identified from the external surface of O. paulistanensis. The isolation and identification of pathogenic bacteria, and their synanthropic behavior, adds weight to potential role of some flesh flies, as O. paulistanensis, in a sanitary context.

Observation of Giardia sp. in the termite gut of Heterotermes tenuis

Giardia comprises one genus with several morphologically distinct species described in mammals (including humans, marsupials, rodents), birds, and amphibians. This group of protists provokes diarrhoea diseases in humans and animals worldwide. Transmission of the parasite occurs through the faecal-oral route. Regarding the presence of Giardia in invertebrates, some works have shown that flies can transmit Giardia cysts by contact and transport between contaminated faeces and food. In this way, flies would eventually transmit this parasite. To date, Giardia's presence in the gut of other invertebrates has not been described in the literature. Here we show by first time, using scanning electron microscopy, the presence of Giardia-like trophozoites in the gut of termite Heterotermes tenuis. Two groups of Giardia were found based exclusively on the size and the flange shape of the protozoa: one presented eight flagella, a ventral disc, size, and shape very similar to Giardia intestinalis. In contrast, other cells were smaller and showed some differences in the external morphology. We cannot exclude the possibility that they correspond to the same species and that these differences result from protozoan heterogeneity.

Molecular prevalence and genotyping of Giardia duodenalis in cattle in Central Anatolia Region of Turkey

The molecular prevalence and genotypes of Giardia duodenalis in cattle were investigated. A total of 450 fecal samples were collected from cattle in three provinces of Central Anatolia from August 2017 to July 2019. Genomic DNA was extracted from the fecal samples and used in molecular analysis carried out by nested PCR analyses of the β-giardin (bg) gene of G. duodenalis. Positive samples were further analyzed by nested PCR at two gene loci (triosephosphate isomerase (tpi) and glutamate dehydrogenase (gdh)) for genotyping of G. duodenalis isolates. PCR analyses of the bg gene indicated that the overall prevalence of G. duodenalis was 30.2%. However, lower rates were determined with PCR analyses for gdh and tpi loci. The sequence analyses of the bg, gdh, and tpi genes revealed the presence of zoonotic assemblage A and livestock-specific assemblage E. Combined-sequence analyses revealed that assemblage E was the most common in the study area. Our study provides the first data on the wide prevalence of livestock-specific assemblages E in cattle in Turkey. The prevalence of assemblage A in cattle also reveals the importance of cattle for zoonotic transmission of giardiasis in Turkey.

Multi-locus genotyping and phylogenetic analyses of Giardia intestinalis isolates from indigenous goats in Ogun State, Nigeria

Giardiasis is a common gastrointestinal disease of humans and various animal species worldwide. In this study, 302 stool samples were collected from West African Dwarf and Sokoto Red breeds of goats in Ogun State, Nigeria, and screened for Giardia intestinalis coproantigens using enzyme-linked immunosorbent assay (ELISA). The genotypes of G. intestinalis in faecal samples collected from 152 goats raised on selected farms were identified by polymerase chain reaction (PCR) amplification and sequence analyses of the small subunit ribosomal RNA (ssu rRNA), glutamate dehydrogenase (gdh), triosephosphate isomerase (tpi) and β-giardin (bg) genes. Based on ELISA, an overall prevalence of 45.7% was recorded with the infection rates in pre-weaned (60.2%) and post-weaned goat kids (51.5%) being significantly (p < 0.05) higher than in adults (28.2%). Giardia intestinalis DNA was amplified in 31.6% and 29.6% of goat faeces at the ssu rRNA and gdh loci respectively. These were genotyped at the ssu rRNA locus as assemblages B (n = 13) and E (n = 36). Similar results were observed at the gdh locus except that eight isolates contained assemblage E mixed with either assemblage A or B. Additionally, sub-assemblages BI (n = 7) and BIII (n = 2) were identified with up to four single nucleotide polymorphisms (SNPs) occurring in these isolates. Multilocus genotypes (MLG) of all assemblage E isolates were identified using the ssu rRNA and gdh loci while MLG of all isolates containing assemblage B and mixed assemblages were determined after further typing at the tpi and bg loci. Forty-two MLG isolates were identified and these comprised 32, 8 and 2 (sub)-assemblage E, BI and BIII respectively. All isolates with mixed assemblages at the gdh locus were consequently designated as assemblage E by MLG. The assemblage E isolates from goats were genetically related to isolates from cattle, sheep and goats while the assemblage B isolates were related to isolates of human, pig and lemur origin. This suggests that G. intestinalis isolated from goats bred in Ogun State, Nigeria may be capable of cross-species transmission and may be of zoonotic importance.

Parasitic contamination of commonly consumed vegetables in two markets in Ghana

Introduction

Fresh vegetables are an important source of vital nutrients. Poor farming practices and improper washing put consumers at risk of parasitic infections. This study explored the presence of parasitic contamination of commonly-consumed vegetables procured from two markets in Ghana. It also explored the decontamination effects of washing vegetables with different concentrations of saline solution.

Method

Vegetables were procured from two major open markets in Koforidua, Ghana. Vegetables were thoroughly washed twice using 0.0%, 0.45%, 0.9%, 1.5% concentrations of saline solutions. The deposits were examined under the light microscope for the presence of parasites. Smears were made from sediments, stained and observed with Fluorescence microscope to detect any spores or oocysts of Microsporidium sp., and Cryptosporidium sp.

Result

Three hundred and sixty of five types of vegetables were procured. Two hundred and seven (57.5%, 95% Confidence Interval 52.2% - 62.7%) were found to be contaminated with at least one type of parasite. The extent of vegetable contamination was 97.2% (90.3-99.7) of spring onions, 70.8% (58.9-81.0) of lettuce and 50.0% (38.0-62.0) of tomatoes. The commonest parasites were Strongyloides stercoralis (36.4%, 31.4-41.6), Balantidium coli (13.6%, 10.2-17.6) and Cryptosporidium oocyst (11.1%, 8.1-14.8). Parasite recovering rates were 57.5% (52.2-62.7) and 42.2% (37.1-47.5) after first and second washings respectively.

Conclusion

The level of parasite contamination is high and consumption of raw vegetables procured from these markets carry a high risk of parasite infection. Washing vegetables twice with saline was not effective for parasite removal. Improved approaches for washing vegetables before consumption are needed.

Funding

Ensign College-Students Research Award Program of Bob and Lynette Gay.

Koutsoumanis K, Allende A, Alvarez-Ordóñez A, Bolton D, Bover-Cid S, Chemaly M, Davies R, De Cesare A, Herman L, Hilbert F, Lindqvist R, Nauta M, Peixe L, Ru G, Simmons M, Skandamis P, Suffredini E, Cacciò S, Chalmers R, Deplazes P, Devleesschauwer B, Innes E, Romig T, van der Giessen J, Hempen M, Van der Stede Y, Robertson L. Public health risks associated with food-borne parasites

Parasites are important food‐borne pathogens. Their complex lifecycles, varied transmission routes, and prolonged periods between infection and symptoms mean that the public health burden and relative importance of different transmission routes are often difficult to assess. Furthermore, there are challenges in detection and diagnostics, and variations in reporting. A Europe‐focused ranking exercise, using multicriteria decision analysis, identified potentially food‐borne parasites of importance, and that are currently not routinely controlled in food. These are Cryptosporidium spp., Toxoplasma gondii and Echinococcus spp. Infection with these parasites in humans and animals, or their occurrence in food, is not notifiable in all Member States. This Opinion reviews current methods for detection, identification and tracing of these parasites in relevant foods, reviews literature on food‐borne pathways, examines information on their occurrence and persistence in foods, and investigates possible control measures along the food chain. The differences between these three parasites are substantial, but for all there is a paucity of well‐established, standardised, validated methods that can be applied across the range of relevant foods. Furthermore, the prolonged period between infection and clinical symptoms (from several days for Cryptosporidium to years for Echinococcus spp.) means that source attribution studies are very difficult. Nevertheless, our knowledge of the domestic animal lifecycle (involving dogs and livestock) for Echinoccocus granulosus means that this parasite is controllable. For Echinococcus multilocularis, for which the lifecycle involves wildlife (foxes and rodents), control would be expensive and complicated, but could be achieved in targeted areas with sufficient commitment and resources. Quantitative risk assessments have been described for Toxoplasma in meat. However, for T. gondii and Cryptosporidium as faecal contaminants, development of validated detection methods, including survival/infectivity assays and consensus molecular typing protocols, are required for the development of quantitative risk assessments and efficient control measures.

Giardia: an under-reported foodborne parasite

Foodborne zoonotic pathogens are a serious public health issue and result in significant global economic losses. Despite their importance to public health, epidemiological data on foodborne diseases including giardiasis caused by the enteric parasite, Giardia duodenalis, are lacking. This parasite is estimated to cause ∼28.2 million cases of diarrhoea each year due to contamination of food, but very few foodborne outbreaks have been documented due to the limitations of current detection as well as surveillance methods. The current method for the recovery of Giardia cysts from food matrices using immunomagnetic separation requires further standardisation and cost reduction before it can be widely used. It also should incorporate downstream molecular procedures for genotyping, and traceback and viability analyses. Foodborne giardiasis can be potentially controlled through improvements in national disease surveillance systems and the establishment of Hazard Analysis and Critical Control Point interventions across the food chain. Studies are needed to assess the true prevalence and public health impact of foodborne giardiasis.

The Potential Role of Synanthropic Rodents and Flies in the Transmission of Enterocytozoon bieneusi on a Dairy Cattle farm in China

Enterocytozoon bieneusi causes microsporidiosis, a condition with complex epidemiology involving both direct and indirect transmission routes. To assess the potential role of synanthropic rodents and flies in the transmission of this pathogen, a total of 277 cattle fecal samples, 199 synanthropic rodents, and 50 batches of 20 flies were collected from a cattle farm. These samples were screened for the presence of E. bieneusi by PCR and sequencing of the internal transcribed spacer (ITS) region of the rRNA gene. The positive rates of cattle, synanthropic rodents, and flies were 11.9% (33/277), 4.0% (8/199) and 12.0% (6/50), respectively. Nineteen genotypes were identified, including 11 known genotypes (BEB6, I, COS-I, EbpC, D, J, CHS5, CHG1 to CHG3 and CHG14) and eight novel genotypes (named CHC9 to CHC16). The dominant genotype detected in the present study, BEB6, was found in all three categories of hosts. Moreover, human pathogenic genotypes D and EbpC were also observed in both synanthropic rodents and flies. These results demonstrate that synanthropic rodents and flies may act as biological disseminator or mechanical vector in the transmission of microsporidiosis to humans. Efforts should be made to minimize threats from these commensal animals to public health.

Multilocus genotyping of Giardia duodenalis infecting rabbits in Ogun State, Nigeria

Giardiasis is a cosmopolitan gastrointestinal protozoal parasite that infects humans and various animals worldwide. To assess the zoonotic transmission potential of Giardia, molecular characterization is required. We are unaware of any report on the genotypes of Giardia infecting rabbits in Nigeria. Molecular detection and genotyping of Giardia duodenalis were conducted in a herd of adult Chinchilla rabbits (Oryctolagus cuniculus) managed on the Teaching and Research farm of the Federal University of Agriculture, Abeokuta located in a southwestern state of Nigeria by analysis of the small-subunit ribosomal RNA (ssu rRNA), glutamate dehydrogenase (gdh), triosephosphate isomerase (tpi) and beta-giardin (bg) genes. An overall prevalence of 72.3% (60/83) was recorded in the rabbits with no statistically significant (p > .05) influence of sex on the distribution of the infection in the herd. All the 19 isolates amplified at the four genetic loci were identified as G. duodenalis assemblage BIV by multiple alignment analysis of their consensus sequences. Novel nucleotide substitutions were identified in two isolates at the ssu rRNA locus. Phylogenetic analysis revealed that all ssu rRNA genotypes were closely related to G. duodenalis assemblage B of cattle and human origin. Findings of this study suggest that the rabbits harbour potentially zoonotic assemblage BIV that portends a high risk to students and staff of the University who are in regular contact with the animals.

Cryptosporidiosis: A zoonotic disease concern

Cryptosporidiosis is considered to be a crucial zoonotic disease caused by worldwide distributing parasitic protozoa called Cryptosporidium spp. Cryptosporidiosis becomes a major public health and veterinary concern by affecting in human and various host range species of animals. Essentially, its importance of infection is increasing because of the high incidence in young children, immunocompromised persons, or immunodeficiency syndrome patients, especially in HIV/AIDS, and it is also one of the most causes of mortality in those patients who infected with Cryptosporidium spp. as well as young animals. All domestic animal, livestock, wildlife, and human can be potential reservoirs that contribute Cryptosporidium spp. to food and surface waters and transmitted to other hosts through fecal-oral route. The oocyst stage of Cryptosporidium spp. can remain infective and resistant to various environmental exposure and also resistant to many general disinfecting agents including chlorination which normally used in water treatment. Therefore, the understanding of these zoonotic pathogens is very essential in both animal and human health. This review focuses on the biology, life cycle, transmission, diagnosis, treatment, prevention, and control of this protozoan infection to emphasize and remind as the significant One Health problem.

Detection of zoonotic and livestock-specific assemblages of Giardia duodenalis in free-living wild lizards

Giardia duodenalis is a zoonotic parasite that infects the gut of a wide range of vertebrates, including numerous wildlife species. However, little is known about this protozoan parasite in reptiles. Fecal samples from 31 wild lizards were collected in Galicia (northwest Spain) and screened for the presence of Giardia by PCR amplification and sequencing of the ITS1-5.8S-ITS2 region in the ribosomal unit. This allowed detection of the parasite in 5 samples (16.1%), and enabled identification of G. duodenalis assemblage A2 in two samples of Iberian rock lizard (Iberolacerta monticola), G. duodenalis assemblage B in other two samples of I. monticola, and G. duodenalis assemblage E in one sample of Bocage's wall lizard (Podarcis bocagei). The results obtained after PCR amplification and sequencing of the SSU-rDNA gene confirmed the presence of G. duodenalis assemblage A in two samples of I. monticola. This is the first report of G. duodenalis in free-living lizards, although further studies are needed to distinguish between actual infection and mechanical dissemination of cysts. The detection of zoonotic and livestock-specific assemblages of G. duodenalis demonstrates the wide environmental contamination by this parasite, possibly due to human activities.

Association between enteric protozoan parasites and gastrointestinal illness among HIV- and tuberculosis-infected individuals in the Chowke district, southern Mozambique

Human immune deficiency virus (HIV) and tuberculosis (TB) infections remain major public health issues globally, particularly in sub-Saharan Africa. Impairment of both cell-mediated and humoral immunity by HIV and/or TB infections may limit the host's defences against other pathogens, including the diarrheagenic protozoan Cryptosporidium spp., Giardia intestinalis, and Entamoeba histolytica. During September-December 2015 a cross-sectional study was conducted to assess the prevalence and molecular diversity of these enteric parasites among HIV- and/or TB-infected patients at a medical reference centre in Chowke district, southern Mozambique. A total of 99 stool specimens were initially screened by direct microscopy and further confirmed and characterised by molecular methods. DNA sequence analyses of the genes encoding the small subunit ribosomal RNA and the 60-kDa glycoprotein were used for the typing and sub-typing of Cryptosporidium isolates, respectively. G. intestinalis-positive isolates by real-time PCR were subsequently typed at the glutamate dehydrogenase locus. Differential diagnosis of E. histolytica/dispar was achieved by real-time PCR. G. intestinalis (8.1%) was the enteric protozoan more frequently detected, followed by Cryptosporidium spp. (7.1%), and Entamoeba histolytica/dispar (6.1%). Two HIV-infected (but not TB-infected) patients harbour G. intestinalis and Cryptosporidium spp. co-infections. Two (29%) G. intestinalis isolates were successfully characterised, revealing the presence of known AII and novel BIV genotypes. Four (57%) Cryptosporidium isolates were unmistakeable assigned to C. hominis, identifying two (IbA10G2 and IdA22) sub-types. Cryptosporidium infections were not associated to diarrhoea in HIV-positive patients, probably because improved immune function in the affected individuals due to antiretroviral therapy. G. intestinalis was considered a non-opportunistic pathogen, whereas the presence of E. histolytica could not be confirmed by molecular methods. Based on their common presence in the studied clinical population, we recommend the effective diagnosis and treatment of these enteropathogens for improving the management of HIV and TB patients.

Cryptosporidium and Giardia in Africa: current and future challenges

Cryptosporidium and Giardia are important causes of diarrhoeal illness. Adequate knowledge of the molecular diversity and geographical distribution of these parasites and the environmental and climatic variables that influence their prevalence is important for effective control of infection in at-risk populations, yet relatively little is known about the epidemiology of these parasites in Africa. Cryptosporidium is associated with moderate to severe diarrhoea and increased mortality in African countries and both parasites negatively affect child growth and development. Malnutrition and HIV status are also important contributors to the prevalence of Cryptosporidium and Giardia in African countries. Molecular typing of both parasites in humans, domestic animals and wildlife to date indicates a complex picture of both anthroponotic, zoonotic and spill-back transmission cycles that requires further investigation. For Cryptosporidium, the only available drug (nitazoxanide) is ineffective in HIV and malnourished individuals and therefore more effective drugs are a high priority. Several classes of drugs with good efficacy exist for Giardia, but dosing regimens are suboptimal and emerging resistance threatens clinical utility. Climate change and population growth are also predicted to increase both malnutrition and the prevalence of these parasites in water sources. Dedicated and co-ordinated commitments from African governments involving "One Health" initiatives with multidisciplinary teams of veterinarians, medical workers, relevant government authorities, and public health specialists working together are essential to control and prevent the burden of disease caused by these parasites.

Occurrence of Giardia and Cryptosporidium in wild birds in Galicia (Northwest Spain)

Faecal samples were obtained from 433 wild birds being treated in wildlife recovery centres in Galicia (Northwest Spain), between February 2007 and September 2009. The birds belonged to 64 species representing 17 different orders. Giardia cysts and Cryptosporidium oocysts were detected by an immunofluorescence antibody test and identified at the molecular level by established PCR-sequencing methods. The overall prevalence of Giardia was 2·1% and that of Cryptosporidium, 8·3%. To our knowledge, this is the first description of Giardia sp. in Tyto alba and Caprimulgus europaeus; and of Cryptosporidium sp. in Apus apus, Athene noctua, C. europaeus, Falco tinnunculus, Morus bassanus, Parabuteo unicinctus and Strix aluco. Furthermore, the first PCR-sequence confirmed detection of Giardia duodenalis assemblage B in, Buteo buteo, Coturnix coturnix and Pica pica; G. duodenalis assemblage D in Garrulus glandarius; and G. duodenalis assemblage F in Anas platyrhynchos; Cryptosporidium parvum in Accipiter nisus, B. buteo, Milvus migrans, Pernis apivorus and P. pica; and Cryptosporidium meleagridis in Streptopelia turtur. The study findings demonstrate the wide spread of Giardia and Cryptosporidium between wild birds.

Genotyping and subtyping Cryptosporidium parvum and Giardia duodenalis carried by flies on dairy farms in Henan, China

Background

Cryptosporidium and Giardia are important causes of diarrhea diseases in humans and animals worldwide, and both of them are transmitted by the fecal–oral route, either by direct contact or by the ingestion of contaminated food or water. The role of flies in the mechanical transmission of Cryptosporidium and Giardia has been receiving increasing attention. To date, no information is available in China about the occurrence of Cryptosporidium and Giardia in flies. We here investigated Cryptosporidium and Giardia in flies on dairy farms in Henan Province, China, at the genotype and subtype levels.

Methods

Eight hundred flies were randomly collected from two dairy farms from July 2010 to September 2010 and were divided evenly into 40 batches. The fly samples were screened for the presence of Cryptosporidium and Giardia with nested PCR. Cryptosporidium was genotyped and subtyped by analyzing the DNA sequences of small subunit rRNA (SSU rRNA) and 60-kDa glycoprotein (gp60) genes, respectively. The identity of Giardia was determined by sequence analyzing of the triosephosphate isomerase (tpi), glutamate dehydrogenase (gdh), and β-giardin (bg) genes.

Results

Forty batches of flies had 10% of contamination with Cryptosporidium or Giardia, with a mixed infection of the two parasites in one batch of flies. The Cryptosporidium isolates were identified as C. parvum at the SSU rRNA locus, and all belonged to subtype IIdA19G1 at the gp60 locus. The Giardia isolates were all identified as assemblage E of G. duodenalis at the tpi, gdh, and bg loci. One novel subtype of assemblage E was identified based on the gdh and bg loci.

Conclusions

This is the first molecular study of Cryptosporidium and Giardia in flies identified at both genotype and subtype levels. SSU rRNA and gp60 sequences of C. parvum in flies was 100% homologous with those derived from humans, suggesting flies act as an epidemiological vector of zoonotic cryptosporidiosis. The variable PCR efficiencies observed in the analysis of Giardia at different loci suggest that we should use the multilocus genotyping tool in future studies to increase the detection rate, and importantly, to obtain more complete genetic information on Giardia isolates.

Zoonotic cryptosporidiosis in the UK - challenges for control

The protozoan parasite Cryptosporidium infects all classes of vertebrates. Of the major human pathogenic species, Cryptosporidium parvum and Cryptosporidium hominis predominate in the UK. Cryptosporidium hominis is a human-adapted species, while C. parvum has many animal hosts and is particularly common in preweaned farmed ruminants. Evaluation of zoonotic risks has been provided mainly by descriptive and analytical epidemiological studies and enhanced recently by genetic typing of isolates. The robust nature of the transmissive oocyst stage, multiple transmission routes, lack of antiparasitic treatment options and vaccines, and resistance to chlorine disinfection present challenges for control. Subtyping C. parvum isolates has been used to link human cases and suspected sources of infection in sporadic cases and outbreaks. Although it is possible that all C. parvum isolates are potentially zoonotic, populations with and without farm animal linkage have been identified. New zoonotic risks have emerged in at least one outbreak, caused by the Cryptosporidium sp. rabbit genotype. This re-enforces the need to characterize infecting and contaminating isolates to ensure appropriate interventions. This study describes the risks of zoonotic cryptosporidiosis by detailing the hosts providing a potential reservoir, the risks of transmission to humans, outbreaks in animal-associated settings and guidance for control with special emphasis on the UK.

Camelid herd health

The area of herd health is particularly important when considering camelid operations because of the high frequency of travel for exhibition, breeding, and boarding. This article outlines the considerations for routine husbandry, facility and animal maintenance, and infectious disease control in the form of biosecurity, vaccination, and health testing that should be included in any farm's herd-health plan. Veterinary input into the design of programs for biosecurity and infectious disease prevention is critical and requires an active veterinary client-patient relationship with identification of the goals of the operation. Risk assessments should be made based on farm activities and should be the foundation for herd-health program design.

A longitudinal study of Giardia duodenalis genotypes in dairy cows from birth to 2 years of age

Fecal specimens were collected from 30 calves from birth to 24 months of age at a dairy farm in Maryland to determine the prevalence of Giardia duodenalis genotypes in cattle of different ages. Fecal samples were subjected to density gradient centrifugation to remove debris and concentrate cysts. Specimens were analyzed by immunofluorescence microscopy and polymerase chain reaction (PCR). All PCR positive specimens were sequenced using the SSU-rRNA gene of Giardia. All 30 calves shed G. duodenalis cysts at some time during the study. Of 990 specimens, 312 were positive for G. duodenalis (31.5%). The highest prevalence of infection occurred at weeks 4 and 5 of age with 25 out of 30 calves shedding cysts at those sampling times. Overall, pre-weaned calves (<8 weeks of age) exhibited the highest prevalence (60.8%), followed by post-weaned calves (3-12 months of age) (32.1%) and heifers (12-24 months of age) (11.4%). Sequence analysis of the 312 PCR-positive samples revealed the presence of both Assemblages A and E, G. duodenalis, with cumulative prevalences of 70% and 100%, respectively. Assemblage A was not detected in pre-weaned calves, but was detected in 6.9% and 4.7% of post-weaned calves and heifers, respectively. These data indicate not only that calves are infected with both Assemblages A and E simultaneously, but also that infections with zoonotic Assemblage A, G. duodenalis are more common than previously reported. Thus, calves appear to be a more significant reservoir of human infectious G. duodenalis than previous data have suggested.

Research priorities for coordinating management of food safety and water quality

Efforts to exclude disease organisms from farms growing irrigated lettuce and leafy vegetables on California's central coast are conflicting with traditionally accepted strategies to protect surface water quality. To begin resolving this dilemma, over 100 officials, researchers, and industry representatives gathered in April 2007 to set research priorities that could lead to effective co-management of both food safety and water quality. Following the meeting, research priorities were refined and ordered by way of a Delphi process completed by 35 meeting participants. Although water quality and food safety experts conceptualized the issues differently, there were no deep disagreements with respect to research needs. Top priority was given to investigating the fate of pathogens potentially present on farms. Intermediate priorities included characterizing the influence of specific farm management practices on food safety and improving our understanding of vector processes. A scientific subdiscipline focusing on competing risks is needed to characterize and resolve conflicts between human and environmental health.

A longitudinal study of cryptosporidiosis in dairy cattle from birth to 2 years of age

Fecal specimens were collected from 30 calves from birth to 24 months of age at a dairy farm in Maryland to determine the prevalence and age distribution of Cryptosporidium species/genotypes. After centrifugation to remove debris and concentrate oocysts, specimens were examined by immunofluorescence microscopy and polymerase chain reaction (PCR). Fragments of the SSU-rDNA gene amplified by PCR were purified and PCR products were sequenced. All 30 calves shed Cryptosporidium oocysts at some time during the 24 months of the study. Of 990 specimens, 190 were Cryptosporidium-positive (19.2%). The highest prevalence of infection was at 2 weeks of age when 29 of the 30 calves were excreting oocysts. Prevalence was higher in pre-weaned calves (1-8 weeks of age) (45.8%) than in post-weaned calves (3-12 months of age) (18.5%) and heifers (12-24 months of age) (2.2%). Sequence data for 190 PCR-positive specimens identified: C. parvum, C. bovis, the Cryptosporidium deer-like genotype and C. andersoni, with cumulative prevalences of 100, 80, 60, and 3.3%, respectively. C. parvum constituted 97% of infections in pre-weaned calves but only 4% and 0% of infections in post-weaned calves and heifers, respectively. All C. parvum GP60 nucleotide sequences were subtype IIaA15G2R1.