Hammondia isolated from dogs and foxes are genetically distinct

Hammondia heydorni is regarded as a protozoan parasite that uses canids, e.g. dogs and foxes, as definitive hosts, but clinical signs of infection are rare. This study therefore took advantage of the opportunity to study an oocyst population from the faeces of a dog suffering from intermittent bouts of diarrhoea. Oocysts from the naturally infected dog were shown to be H. heydorni by using the polymerase chain reaction combined with DNA sequencing as a diagnostic tool.† A comparison of the first internal transcribed spacer (ITS1) sequence of ribosomal DNA obtained with those from other dog and fox oocysts, previously regarded as H. heydorni, showed these oocysts contained identical ITS1 sequences. However, the oocyst DNA from the fox and dog differed by the presence/absence of a 9 bp insertion/deletion within intron 1 of the alpha tubulin gene, and this difference was conserved across a number of different oocyst populations from the 2 species of host. A PCR assay was established that takes advantage of this insertion/deletion and is able to differentiate between the 2 oocyst populations. This study therefore provides evidence that H. heydorni oocysts from dogs and foxes represent 2 distinct genetic lineages that can be differentiated using a PCR, which targets the alpha tubulin locus. © 2005 Cambridge University Press

SEROPREVALENCE OF TOXOPLASMA GONDII AND NEOSPORA CANINUM IN URBAN AND RURAL DOGS FROM SOUTHWESTERN NIGERIA

Background: Toxoplasma gondii and Neospora caninum are protozoans infecting a wide range of mammals; the etiologic agents of Toxoplasmosis and Neosporosis respectively, This study investigated the prevalence of antibodies to Toxoplasma gondii and Neospora caninum in dogs from southwestern Nigeria. Materials and Methods: A total of 233 serum samples were obtained from both urban and rural areas of Oyo state, Nigeria and tested by the western blotting technique for specific IgG to T. gondii and N. caninum. Results: The seroprevalence obtained for T. gondii was 19% (44/233) and 2.1% (5/233) for N. caninum in the dogs examined. Overall, the prevalence of antibodies to T. gondii was more significant than for N. caninum (P< 0.0001). T. gondii infection was also found to be more significant in roaming than in caged dogs (P< 0.05). There was no significant association of other factors (age, breed, history of rabies vaccination, use of dog and the level of education of owner) with the prevalence of T. gondii and N. caninum infection. Conclusion: This report revealed that T. gondii infection is more common than N. caninum infection in Nigerian dogs, it suggests that improper housing and feeding of dogs could increase the risk of exposure to T. gondii infection. This is the first study to investigate the seroprevalence of N. caninum antibodies in Nigerian dogs and T. gondii antibodies in dogs in southwestern Nigeria

Naturally Acquired Bovine Besnoitiosis

The pathogenesis of bovine besnoitiosis, a disease of increasing concern within Europe, is still incompletely understood. In this study, disease progression after natural infection with the causative apicomplexan Besnoitia besnoiti was monitored in histological skin sections of 5 individual female cattle over time. High-frequency skin sampling of 2 cattle with mild and 2 with severe acute, subacute, and chronic besnoitiosis, as well as from 1 animal during subclinical disease, enabled documentation from the beginning of the disease. Skin sections were stained with hematoxylin and eosin and Giemsa, periodic acid–Schiff reaction, and anti-Besnoitia immunohistochemistry. In all 4 clinically affected animals, tachyzoite-like endozoites could be detected for the first time by immunohistochemistry, and tissue cyst evolution was monitored. Besnoitiosis-associated lesions were not detected in the animal showing the subclinical course. Because of the inconsistency of the nomenclature of Besnoitia tissue cyst layers in the literature, a new nomenclature for B. besnoiti cyst wall layers is proposed: tissue cysts consist of a hypertrophied host cell with enlarged nuclei, an intracytoplasmic parasitophorous vacuole with bradyzoites, a sometimes vacuolated inner cyst wall, and an outer cyst wall in more developed cysts. Inner and outer cyst walls can be readily distinguished by using special stains. In 1 animal, extracystic B. besnoiti zoites were immunohistochemically detected during the chronic stage. At necropsy, the 2 severely affected cows displayed large numbers of B. besnoiti cysts in a variety of tissues, including the corium of the claws, contributing mainly to the development of chronic laminitis in these 2 cases

Assessment of the parasitic burden in smallholder pig value chains and implications for public health in Uganda

Pig production has only recently become a popular income-generating activity among smallholder farmers in Uganda; over the past 30 years, pig numbers have increased by a tenfold and pork consumption in East Africa is highest in Uganda. Pigs are not a traditional livestock species to Uganda and little is known about the occurrence of parasitic diseases that reduce growth performance and may have implications for public health. An initial systematic literature review conducted by Ocaido et al. (forthcoming), revealed huge data gaps as most zoonotic pig parasites have never been researched in East Africa. As part of comprehensive smallholder pig value chain assessments carried out by the International Livestock Research Institute (ILRI) in three administrative districts of Uganda, the presence and importance of pig parasites along the food chain was investigated. Thirty-five focus group discussions with more than 300 pig farmers showed that parasites are perceived to be a big production constraint with intestinal worms and sarcoptic mange ranking second and third after swine fever (Dione et al., 2014). Knowledge about zoonotic pig parasites is limited and practices such as free-ranging and tethering, erratic treatment and self-medication as well as lack of good hygiene on farm are common. This study presents preliminary findings on parasitic diseases that potentially compromise farm productivity (e.g. gastrointestinal helminths and sarcoptic mange) and public health (e.g. Trypanosoma spp., Trichinella spp. and Toxoplasma gondii). The research was carried out with the financial support of the Federal Ministry for Economic Cooperation and Development, Germany, and the CGIAR Research Program on Agriculture for Nutrition and Health, led by the International Food Policy Research Institute, through the Safe Food, Fair Food project at ILRI

Chicken line-dependent mortality after experimental infection with three type IIxIII recombinant Toxoplasma gondii clones

Three genetically different clones of Toxoplasma gondii, also different in mouse virulence, were studied by experimental infection in chickens. For the experiments, four chicken lines were used, which differed in phylogenetic origin and performance level: two white egg layer lines, one with high laying performance (WLA), one with low (R11) and two brown layer lines, also displaying high (BLA) and low (L68) egg number. Chickens were intraperitoneally infected with three different T. gondii isolates representing type IIxIII recombinant clones, i.e. showing both, type II- and type III-specific alleles. These clones (K119/2 2C10, B136/1 B6H6, K119/2 A7) had exhibited virulence differences in a mouse model. In chickens, a significantly higher mortality was observed in white layer lines, but not in brown layer lines, suggesting that differences in the phylogenetic background may influence the susceptibility of chickens for toxoplasmosis. In addition, antibody (IgY) levels varied in surviving chickens at 31 days post infection. While low to intermediate antibody levels were observed in white layers, intermediate to high levels were measured in brown layers. Infection with a T. gondii clone showing low chicken virulence resulted in higher antibody levels in all chicken lines compared to infection with T. gondii clones of intermediate or high chicken virulence. This was in agreement with the parasite load as determined by real-time PCR. Overall, results show that progeny resulting from natural sexual recombination of T. gondii clonal lineages, may differ in their virulence for mice and chickens.Facultad de Ciencias Veterinaria

Toxoplasma gondii infection and toxoplasmosis in farm animals: Risk factors and economic impact

The protozoan parasite Toxoplasma gondii is a zoonotic parasite that can be transmitted from animals to humans. Felids, including domestic cats, are definitive hosts that can shed oocysts with their feces. In addition to infections that occur by accidental oral uptake of food or water contaminated with oocysts, it is assumed that a large proportion of affected humans may have become infected by consuming meat or other animal products that contained infective parasitic stages of T. gondii. Since farm animals represent a direct source of infection for humans, but also a possible reservoir for the parasite, it is important to control T. gondii infections in livestock. Moreover, T. gondii may also be pathogenic to livestock where it could be responsible for considerable economic losses in some regions and particular farming systems, e.g. in areas where the small ruminant industry is relevant. This review aims to summarize actual knowledge on the prevalence and effects of infections with T. gondii in the most important livestock species and on the effects of toxoplasmosis on livestock. It also provides an overview on potential risk factors favoring infections of livestock with T. gondii. Knowledge on potential risk factors is prerequisite to implement effective biosecurity measures on farms to prevent T. gondii infections. Risk factors identified by many studies are cat-related, but also those associated with a potential contamination of fodder or water, and with access to a potentially contaminated environment. Published information on the costs T. gondii infections cause in livestock production, is scarce. The most recent peer reviewed reports from Great Britain and Uruguay suggest annual cost of about 5–15 million US $ per country. Since these estimates are outdated, future studies are needed to estimate the present costs due to toxoplasmosis in livestock. Further, the fact that T. gondii infections in livestock may affect human health needs to be considered and the respective costs should also be estimated, but this is beyond the scope of this article

Fatal disseminated Toxoplasma gondii infection in a captive harbour porpoise (Phocoena phocoena)

A 7-year-old female harbour porpoise (Phocoena phocoena), born and held in captivity, suffered from reduced consciousness, imprecise and circling swimming movements and long phases of immobility over a period of 3 weeks. The animal died during treatment in a Danish open sea facility. Pathological examination revealed multifocal pyogranulomatous to necrotizing meningoencephalomyelitis, ganglioneuritis, plexus chorioiditis, myocarditis, hepatitis and adrenalitis with few intralesional protozoal tachyzoites and bradyzoites within cysts. Immunohistochemistry was positive for Toxoplasma gondii antigen within the lesions. Using polymerase chain reaction (PCR), the presence of T. gondii-specific genome fragments was confirmed. A multilocus PCR-restriction fragment length polymorphism analysis using nine unlinked marker regions (nSAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico) resulted in the identification of T. gondii type II (variant Apico Type I), which is the T. gondii genotype dominating in Germany. This is the first description of disseminated fatal toxoplasmosis in a captive harbour porpoise that lived in an open sea basin. Surface water contaminated with toxoplasma oocysts is regarded as the most likely source of infection

Gastric nodules with Neospora caninum zooites in a confirmed clinical Neospora caninum infection in a dog

Generalized neosporosis was diagnosed in a two year old rottweiler. The dog had a history of tetraparesis, muscle atrophy, regurgitation and vomiting. Serological analysis by indirect fluorescent antibody test was 1/400 for Neospora caninum. Contrasted radiological surveys showed megaesophagus and during ultrasonografic examination an 8.2 mm diameter mural nodule was observed at the pyloric region. Citologic evaluation revealed highly number of zooites. Microscopically, severe myositis were observed in histologic muscle sections and several groups of tachyzoites and tissue cysts were associated with these lesions. The result of the immunhistochemical staining was: protozoa in muscle sections of the dog stained strongly using 5.2.15 monoclonal antibodies against N. caninum tachyzoites. This paper describes a clinical case of canine neosporosis with vomiting associated to Neospora gastric nodule.Se realizó el diagnóstico de neosporosis generalizada en un canino rottweiler de dos años de edad. El paciente presentaba las siguientes alteraciones: tetraparesia, atrofia muscular, regurgitación y vómito. El resultado del análisis serológico por prueba de inmunofluoresencia indirecta fue 1/400 para Neospora caninum. Los estudios radiológicos contrastados mostraron megaesófago y durante el examen ultrasonográfico se observó un nódulo mural de 8,2 mm de diámetro en la región pilórica. La evaluación citológica reveló numerosos zooítos. En las secciones histológicas de músculo se observaron varios grupos de taquizoitos y quistes asociados a miositis severa. El resultado de las técnicas de immunohistoquímica fue: protozoos en secciones de músculo que se tiñeron fuertemente con 5.2.15 anticuerpos monoclonales contra taquizoitos de N. caninum. Este reporte describe un caso clínico de neosporosis canina con vómitos asociados a nódulo gástrico de Neospora