Enhanced detection of Cryptosporidium parvum in the acid-fast stain

Prevalence of Cryptosporidium spp. infection in a working horse population in Egypt

Working horses support the livelihoods of smallholder farmers in Egypt. No previous study has investigated the prevalence of cryptosporidiosis in working horses in Egypt. Faecal samples were collected from 607 working horses recruited from thirty-seven villages/areas in two Egyptian governorates and examined for Cryptosporidium spp. infection using the modified Zielh-Neelsen staining technique. Data on signalment, history of recent diarrhoea, and strongyle burden were collected. The prevalence of Cryptosporidium spp. infection was calculated using a bootstrap method and potential risk factors for infection were investigated using mixed-effects logistic regression models that included sampling location as a random-effects variable. The prevalence of Cryptosporidium spp. infection was 28.7% (95% confidence interval = 23.5-33.9). None of the variables investigated, which include age, sex of the animals, and strongyle burden, were associated with risk of infection. This study provided evidence-based information on the prevalence of Cryptosporidium spp. infection in the study area. However, the potential zoonotic risk of Cryptosporidium cannot be confirmed until further studies are conducted to genotype these parasites.

Prevalence of Cryptosporidium spp. infection in working horses in Egypt.. [DOI: 10.21203/rs.3.rs-2363022/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Working horses support the livelihoods of smallholder farmers in Egypt but can pose potential zoonotic risk to their handlers such as cryptosporidiosis. Working horses were recruited into the study from 37 villages/areas in two Egyptian governorates. Faecal samples were collected from 607 horses and were examined for Cryptosporidium spp. infection using modified Zielh-Neelsen staining technique. Data about signalment, concurrent disease and level of strongyle infection were collected. The prevalence of Cryptosporidium spp. infection was calculated using a bootstrap method and potential risk factors for the infection were investigated using mixed-effects logistic regression models that included the sampling location as a random-effects variable. The prevalence of Cryptosporidium spp. infection was 28.7% (95% confidence interval = 23.5–33.9). None of the variables investigated including age and sex of the animals were associated with the risk of the infection. The study identified greater prevalence of Cryptosporidium spp. infection in the study area and further studies may be required to genotype these parasites. Personal hygiene such as hand sanitation should be practiced when managing these horses.

Sensitive detection of C. parvum using near infrared emitting Ag2S@silica core–shell nanospheres

Optical detection ofC. parvumin environmental samples using anti-oocysts McAb immobilized NIR emitting Ag₂S@silica core–shell nanospheres as immunosensors is reported.

Epidemiological characteristics of the first water-borne outbreak of cryptosporidiosis in Seoul, Korea

The first case of human cryptosporidiosis was reported in Korea in 1995; however, an outbreak of Cryptosporidium has not been reported in Korea until now. This paper describes the first outbreak of cryptosporidiosis in Korea. On May 24, 2012, a local public health center filed a report on 126 residents with gastrointestinal symptoms in an old apartment complex in Seoul. Epidemiological investigations were implemented on 125 of the 126 patients. The patients were reported continuously over a period of 22 days. Diarrhea was the most common clinical symptom, and lasted for 5 days on average. The tap water was the only common exposure of the patients. During the environmental investigation it was discovered that the water and septic tanks were situated closely and that the waste water pipes were corroded where they passed over the water pipes. Cryptosporidium parvum was detected in 3 of the 7 stool specimens by PCR-RFLP. A number of Cryptosporidium oocysts were also detected in the water specimens from the water tank. In conclusion, Cryptosporidium parvum was the key causal pathogen of this outbreak. It is presumed that the tap water was contaminated by a sewage leak from the aged pipelines.

Cryptosporidium recovered from Musca domestica, Musca sorbens and mango juice accessed by synanthropic flies in Bahirdar, Ethiopia

The study was conducted to determine the role of house flies, Musca domestica and Musca sorbens to carry Cryptosporidium species in natural environment and filth flies potential for contamination of food item they visited using acid-fast stain technique. Cryptosporidium was identified from flies collected in dairy cow barns, butchery, market and defecating grounds. Musca domestica captured from dairy cow barns and M. sorbens from defecating ground were found carrying more oocyst of Cryptosporidium parvum. Oocyst load per fly for M. domestica and M. sorbens was 5.84 and 3.42, respectively. Flies' population dynamics in each month had little relation to the monthly oocyst frequency, r = 0.06 and 0.02 for M. domestica and M. sorbens, respectively. Cryptosporidium species oocysts were isolated from frozen mango juice, which filth flies visited in dairy farm barn. Load of oocysts in the mango juice was dependent on time contact of flies with mango juice and more oocysts were recovered (P < 0.05) in mango juice samples accessed by filth flies for longer period. Role of filth flies to carry and deposit Cryptosporidium species oocyst for development of food-borne cryptosporidiosis is signified.

Development of a sensitive detection system for Cryptosporidium in environmental samples

The identification of Cryptosporidium species and genotypes is necessary to determine sources of infection in outbreaks and the risk factors associated with their transmission. Few studies have applied isolation methods to field samples because of difficulties with detection of oocysts in environmental samples, particularly in soil and manure. The objective of this study was to develop an easy to use method which can be applied to field samples to rapidly detect the presence of Cryptosporidium parasites and identify their species. The assay included an oocyst recovery method combined with spin column DNA extraction, followed by PCR-hybridization for detection and a real-time PCR-melting curve analysis for species assignment. An internal positive control (IPC) was developed to determine the presence of PCR inhibitory substances. Two oocyst recovery methods, sodium chloride and sucrose flotation techniques were compared. Two commercial DNA extraction kits were performed using feces, soil and water samples each inoculated with different concentration of Cryptosporidium oocysts. Subsequently, methods were used to test field samples. The sucrose flotation method provided the greatest analytical sensitivity detecting as few as 10 oocysts. The PCR-hybridization detection limit was 10 oocysts for feces and soil, and less than 10 oocysts for water samples. IPC was positive for all inoculated and field samples indicating 0% PCR inhibition. Cryptosporidium species DNA samples were detected with the real-time PCR and were differentiated by the melting curve analysis. The results of this study demonstrate the potential of the assay system for rapid detection of Cryptosporidium parasites in environmental samples.

A review of the biology and epidemiology of cryptosporidiosis in humans and animals

The epidemiology of cryptosporidiosis, an infection caused by several genotypically and phenotypically diverse Cryptosporidium species, has been dynamically changing over the past decade from that of a rare, largely asymptomatic infection to an acute enteric disease of animals and humans. In this review, the current understanding of factors (biology and epidemiology) contributing to the emergence of cryptosporidiosis in animals, including parasite biology, genetic diversity, environmental spread, livestock production trends, presence of the parasite in livestock and companion animals, and potential risk of transmission from animals to humans is highlighted. Potential control measures and the role of veterinary and medical professionals in the prevention of cryptosporidiosis are also discussed.

Association of enteric shedding of bovine torovirus (Breda virus) and other enteropathogens with diarrhea in veal calves

OBJECTIVE

To determine the prevalence, fecal shedding pattern, and association of bovine torovirus (BoTV) with diarrhea in veal calves at time of arrival and periodically throughout the first 35 days after their arrival on a veal farm.

ANIMALS

62 veal calves.

PROCEDURE

Fecal samples collected on days 0, 4, 14, and 35 after arrival were tested for BoTV by use of ELISA and reverse transcriptase-polymerase chain reaction (RT-PCR) assay. Paired serum samples obtained from blood collected on days 0 and 35 were analyzed for BoTV antibodies with a hemagglutination inhibition assay. Fecal samples were also screened for other enteric pathogens, including rotavirus, coronavirus, and Cryptosporidium spp.

RESULTS

Fecal shedding of BoTV was detected in 15 of 62 (24%) calves by use of ELISA and RT-PCR assay, with peak shedding on day 4. A significant independent association between BoTV shedding and diarrhea was observed. In addition, calves shedding > or = 2 enteric pathogens were more likely to have diarrhea than calves shedding < or = 1 pathogen. Calves that were seronegative or had low antibody titers against BoTV (< or = 1:10 hemagglutination inhibition units) at arrival seroconverted to BoTV (> 4-fold increase in titer); these calves were more likely to shed virus than calves that were seropositive against BoTV at arrival.

CONCLUSIONS AND CLINICAL RELEVANCE

Shedding of BoTV was strongly associated with diarrhea in neonatal veal calves during the first week after arrival at the farm. These data provide evidence that BoTV is an important pathogen of neonatal veal calves.

Cryptosporidium hominis n. sp. (Apicomplexa: Cryptosporidiidae) from Homo sapiens

The structure and infectivity of the oocysts of a new species of Cryptosporidium from the feces of humans are described. Oocysts are structurally indistinguishable from those of Cryptosporidium parvum. Oocysts of the new species are passed fully sporulated, lack sporocysts. and measure 4.4-5.4 microm (mean = 4.86) x 4.4-5.9 microm (mean = 5.2 microm) with a length to width ratio 1.0-1.09 (mean 1.07) (n = 100). Oocysts were not infectious for ARC Swiss mice, nude mice. Wistar rat pups, puppies, kittens or calves, but were infectious to neonatal gnotobiotic pigs. Pathogenicity studies in the gnotobiotic pig model revealed significant differences in parasite-associated lesion distribution (P = 0.005 to P = 0.02) and intensity of infection (P = 0.04) between C. parvum and this newly described species from humans. In vitro cultivation studies have also revealed growth differences between the two species. Multi-locus analysis of numerous unlinked loci, including a preliminary sequence scan of the entire genome demonstrated this species to be distinct from C. parvum and also demonstrated a lack of recombination, providing further support for its species status. Based on biological and molecular data, this Cryptosporidium infecting the intestine of humans is proposed to be a new species Cryptosporidium hominis n. sp.

Rapid methods to isolate Cryptosporidium DNA from frozen feces for PCR

The polymerase chain reaction (PCR) offers one of the most sensitive methods for detecting Cryptosporidium parvum but its sensitivity in fecal material can be greatly reduced by a variety of poorly defined 'inhibitors'. Methods that separate the parasitic oocyst from fecal material prior to DNA extraction circumvent inhibitor interference but are problematic for frozen specimens since 'intact' oocysts are required for separation. We report here a relatively low-cost, rapid method for extracting C. parvum DNA from frozen fecal materials that can be used in a PCR assay for detection of single parasitic oocysts.