Rapid diagnosis of bovine cryptosporidiosis with a modified commercial acid-fast staining procedure

Comparison between two commercially available serological tests and polymerase chain reaction in the diagnosis of Cryptosporidium in animals and diarrhoeic children

For the detection of Cryptosporidium species in 804 animals and 165 diarrhoeic children (<10 years) in Egypt, two copro-antigen tests, the RIDASCREEN® Cryptosporidium test [enzyme immunoassay (EIA)] and the RIDA®QUICK Cryptosporidium/Giardia Combi [immuno-chromatographic test (ICT)] as well as polymerase chain reaction (PCR) were used. Prevalence of Cryptosporidium was 15.0, 19.5 and 32.3% in animals and 2.4, 6.7 and 49.1% in children using EIA, ICT and PCR, respectively.Using PCR as reference method, animal samples sensitivity (Se) of the EIA was 46.5% when questionable samples were considered positive, whereas specificity (Sp) was 100%. Se of the ICT was 60.4% while Sp was 100%. Positive predictive values (PPVs) for both EIA and ICT test were 100%, and negative predictive values (NPVs) for EIA were 79.7 and 84.1% for ICT. For the children samples, the Se of EIA was 5%, Sp was 100%, PPV was 100% and NPV was 52.2%, while the Se of ICT was 13.6%, Sp was 100%, PPV was 100% and NPV was 54.6%.The Kappa score of agreement between PCR and ICT was 67.4%, 54.1% between PCR and EIA and 84.4% between ICT and EIA. Until the second serial dilution of the EIA and ICT test, 9 × 10(3) oocysts/μl of Cryptosporidia was detected, whereas in PCR, they were detected until the sixth serial dilution. Copro-antigen tests were easy to perform and less time-consuming but less sensitive compared to PCR. They obviously are best applicable for screening and epidemiological studies of large numbers of subjects, for batch specimen processing and in isolated or rural areas where reliable tests like PCR are unfeasible. When in children, a single stool sample is used for the diagnosis of clinical cases; better results can be obtained when non-standardized PCR due low specificity is coupled with copro-antigen tests.

Molecular epidemiology of Cryptosporidium in livestock animals and humans in the Ismailia province of Egypt

The zoonotic potential of Cryptosporidium was studied in one of the most densely populated provinces of Egypt regarding livestock and people. In a representative survey, faecal samples from cattle, buffalo and stool samples from diarrhoeic children (<10 years) were investigated. Parameters assumed to be related to cryptosporidiosis were recorded for animals and children. Animal samples (804) were examined by the Copro-antigen RIDA(®)QUICK test, followed by PCRs targeting the 18S rDNA and gp60 genes for antigen-positive and 10% randomly selected negative samples. All 165 human samples were tested by both methods. The overall estimated prevalence of Cryptosporidium in ruminants was 32.2%, without significant difference between animal species. PCR identified 65.7% Cryptosporidium parvum, 11.8% Cryptosporidium ryanae, 4.1% Cryptosporidium bovis, and combinations of C. parvum plus C. ryanae (11.2%), C. parvum plus C. bovis (5.3%) and of C. parvum plus Cryptosporidium andersoni (1.8%), also without significant differences in species occurrence between cattle and buffalos. The human Cryptosporidium spp. prevalence was 49.1%, of which 60.5% were Cryptosporidium hominis, 38.2% C. parvum and 1.2% C. parvum plus C. bovis. Analysis of gp60 variants allocated C. parvum found in animals to the zoonotic subtype family IIa (18.9%, subtype IIaA15G1R1 only) and to IId (81.1%, mostly IIdA20G1). In humans 50% were classified as subtype family IIa (IIaA15G1R1 and IIaA15G2R1) and 50% were IIdA20G1. C. andersoni occurred only in cattle older than 1 year. In contrast, mono-infections with one of the three single Cryptosporidium species and the three combinations with C. parvum were more prevalent in cattle and buffaloes younger than 1 year, particularly in those younger than 3 months, and were predominantly subtype family IId. In human samples no Cryptosporidium were identified in children younger than 7 months. Neither place of residence nor the source of drinking-water had measurable effects on prevalence. Remarkably, however, all children with C. parvum subtype family IIa and 86% with subtype family IId had contact to animals. High prevalence and identical genotypes of C. parvum in animals and humans indicate zoonotic transmission due to contact with animals, involving IIdA20G1 as the most frequent subtype.

Manure and microbes: public and animal health problem?

Most environmental concerns about waste management either have focused on the effects of nutrients, especially N and P, on water quality or have emphasized odor problems and air quality. Microbes from manure are often low on the priority list for control and remediation, despite the fact that several outbreaks of gastroenteritis have been traced to livestock operations. The pathogens discussed in this paper include protozoans (Cryptosporidium parvum, Giardia spp.), bacteria (Listeria monocytogenes, Escherichia coli O157:H7, Salmonella spp., and Mycobacterium paratuberculosis), and some enteric viruses. Clinical symptoms, prospects for zoonotic infection, and control methods other than the use of antimicrobials are considered. Recommendations to avoid disease transmission include taking steps to ensure the provision of clean, unstressful environments to reduce disease susceptibility and the careful handling and spreading of manure from animals at high risk for infection, especially young calves. Composting and drying of manure decrease the number of viable pathogens. Environmental controls, such as filter strips, also reduce the risk of water contamination.

Intestinal protozoa infections

This article reviews important intestinal protozoal infections in cats. Among intestinal protozoa, Giardia and coccidia are the most important infections. Giardiasis is a common problem in catteries, especially where young kittens run free on the floor. Overcrowding and high humidity favour the survival and transmission of Giardia. Diagnosis is made by fecal examination by direct or concentration methods. Metronidazole is the drug of choice for treating giardiasis. Among the coccidial parasites, Isospora felis and Cryptosporidium sp. are the common infections. Virtually all cats become infected with Isospora felis. The pathogenicity of I. felis is controversial. Cryptosporidium parvum infection is a zoonosis. Cryptosporidium is transmitted by direct fecal-oral cycle. Cryptosporidial infections appear to be clinical in immunosuppressed cats. No drug has been found satisfactory for treatment of cryptosporidiosis.