Bovine hypodermosis is highly prevalent in Kazakhstan: Results of a first serological study

Background and Aim

Recent information on the occurrence of bovine hypodermosis in Kazakhstan is limited to the results of a few clinical studies in the northern and eastern regions. A first serological study aimed to obtain more data on its geographical distribution and to estimate the prevalence in this country.

Material and Methods

Serum samples collected from 891 dairy cows on 30 dairy farms in eight Kazakh provinces during the winter season 2015/2016 were examined for antibodies to Hypoderma spp. first-stage larval antigen using a commercially available enzyme-linked immunosorbent assay (IDEXX Bovine Hypodermosis Serum Antibody Test).

Results

Overall, 73.6% (95% confidence interval: 70.6%-76.5%) of the cows sampled were seropositive for Hypoderma, and antibody-positive cows were found in 28 of 30 farms and in seven of eight provinces.

Conclusion

The results suggest a high prevalence of bovine hypodermosis in Kazakhstan, for which the socioeconomic changes in agriculture and village life following the country's independence are considered to be responsible.

Morpho-phylogenetic evidence reveals new species in Rhytismataceae (Rhytismatales, Leotiomycetes, Ascomycota) from Guizhou Province, China

Karst formations represent a unique eco-environment. Research in the microfungi inhabiting this area is limited. During an ongoing survey of ascomycetous microfungi from karst terrains in Guizhou Province, China, we discovered four new species, which are introduced here as Hypodermaparalinderae, Terrierakarsti, T.meitanensis and T.sigmoideospora placed in Rhytismataceae, based on phylogenetic analyses and morphological characters. Molecular analyses, based on concatenated LSU-ITS-mtSSU sequence data, were used to infer phylogenetic affinities. Detail descriptions and comprehensive illustrations of these new taxa are provided and relationships with the allied species are discussed, based on comparative morphology and molecular data.

Cytokine expression in bovine PBMC cultures stimulated with Hypoderma lineatum antigens

Hypoderma antigens are involved in host inflammation and immune response, conditioning larvae survival. In this study, peripheral blood mononuclear cell (PBMC) cultures from Hypoderma sensitized and unsensitized cattle were performed to determine the effect of H. lineatum antigens and incubation time (18, 24, 48 h) on IFN-γ, TNF-α, IL-10 and IL-4 mRNA gene expression determined by RT-qPCR. TNF-α and IL-4 gene expression were higher in Hypoderma previously sensitized PBMCs, suggesting that a mixed Th1/Th2 response may play a significant role in host defence reactions against Hypoderma exhibited by previously infested cattle. Incubation time had a significant effect on IL-10 and TNF-α gene expression, which decreased over time. Regarding to H. lineatum antigens, the crude larval extract and the purified fraction hypodermin B (HB) produced a significant reduction of the mRNA expression levels of the proinflammatory cytokine, IFN-γ; moreover, the HB had a stimulating effect on the mRNA gene expression of the anti-inflammatory cytokine IL-10, demonstrating that the parasite would modulate the host defence mechanisms by avoiding harmful immune responses that would limit its survival into the host tissues.

Modulatory effects of interferon-γ and interleukin-4 on cellular immune responses against Hypoderma lineatum antigens

This study investigates the in vitro modulatory effects of interferon-γ (IFN-γ) and interleukin-4 (IL-4) on both proliferative bovine T cell responses and IL-10 production induced by different antigens [crude larval extract and the purified fractions hypodermin A, B and C (HyA, HyB, HyC)] obtained from first instars of Hypoderma lineatum (Diptera: Oestridae), alone or in the presence of the mitogen concanavalin A. Incubation with the different parasitic antigens resulted in significant inhibition of T cell proliferation and IL-10 production, which, in general, did not revert after the addition of IFN-γ and IL-4. In the absence of antigens, IL-4 induced significant inhibition of mitogen-induced T cell responses. Exogenous IFN-γ exhibited an inhibitory effect on cell proliferation in the presence of the purified fractions HyB and HyC. These in vitro data suggest that far from neutralizing the effects of larval antigens, the addition of IFN-γ potentiates their anti-proliferative activity; by contrast, IL-4 had no consistent effects on proliferative responses to Hypoderma. IL-4 provoked an increment of IL-10 levels in supernatants of HyB-stimulated cells. In conclusion, exogenous IFN-γ and IL-4 were unable to counteract the suppressor effects of H. lineatum antigens.

Placement of the genus Angelina within Rhytismatales and observations of Angelina rufescens

Angelina rufescens is placed within the core clade of Rhytismatales (Leotiomycetes, Pezizomycotina, Ascomycota) based on analysis of LSU and mtSSU rDNA. The only species in the genus, it produces distinctive ascomata that reoccur annually on wood and on the remains of its own previous fructifications, forming dense conglomerations of interlocking longitudinally elongated apothecia with gray hymenia. Known collections and references of A. rufescens indicate that it is endemic to eastern and central United States. Morphological and cultural characters are described with notes on ascomata development. No mitospores were observed in field collections or in culture. Lectotypes are designated for Hysterium rufescens and its synonym Ascobolus conglomeratus. Angelina rufescens is illustrated here for the first time in the taxonomic literature.