Bovine Cryptosporidium parvum field isolates differ in cytopathogenicity in HCT-8 monolayers.

Suckling calves are prone to Cryptosporidium infection. The variable degree of clinical disease is influenced by keeping conditions and immune status of the host, but diversity of isolate virulence may also contribute. The aim of the current study was to evaluate the cytopathogenic effects of 26 C. parvum field isolates by using a MTT assay in HCT-8 cell monolayers. Cell viability of monolayers inoculated with oocysts of the field isolates varied considerably with values of 17.7% (± 5.1%) to 99.5% (± 7.1%). A standard deviation of 18.6% was detected for cell viability of the in house reference strain, which were tested alongside in every assay. Field isolates were grouped in three categories of cytopathogenicity. Probably the length of storage has an effect on the level of the cell destruction category detected post infection in vitro. The applied tool may help to better understand the variable course of cryptosporidiosis in the field.

Distribution of Cryptosporidium parvum gp60 subtypes in calf herds of Saxony, Germany.

Cryptosporidiosis is a common protozoan parasitic infection that causes diarrhoea in neonatal calves. The high shedding of environmentally resistant oocysts facilitates outbreaks of cryptosporidiosis in humans. In total, 58 farms (512 calves) in Germany (Saxony and Brandenburg) were visited three times each. Faecal samples of pre-weaned calves were microscopically examined for oocysts of Cryptosporidium spp. using Heine staining and were scored with regard to their consistency. Overall, 88.9% of calves tested microscopically positive for Cryptosporidium spp. in at least one sample, and the excretion of oocysts was significantly (P < 0.01) associated with a higher faecal score (diarrhoea). After DNA extraction from pooled farm isolates, 47 samples were successfully subtyped by sequence analysis of the 60 kDa glycoprotein gene (gp60). All isolates belonged to subtype family IIa. IIaA15G2R1 was the most common subtype (present on 66% of the farms), followed by IIaA16G3R1 (13%). Subtypes IIaA14G1R1, IIaA14G2R1, IIaA1612R1, IIaA16G2R1, IIaA17G1R1, IIaA17G2R1, IIaA17G4R1 and IIaA19G2R1 were found sporadically. This is the first description of gp60 subtype IIaA17G4R1 in cattle in Germany.

Climate suitability for the transmission of Dirofilaria immitis and D. repens in Germany.

Recently concerns are increasing that dirofilarial nematodes may spread from endemic areas in southern, eastern and central Europe to countries in northern regions of Europe. The increasing number of autochthonous cases of canine Dirofilaria repens infections in Germany indicates that worms of this genus may invade new areas, and climate change may be a key factor in this scenario. Thus analysis of long term development of regional temperature is a pivotal factor in risk analysis related to transmission of these worms. Such information is important for suggestions of counteracting strategies, such as definition of periods of increased transmission risk and, consequently, time slots most suited for preventative measures. In this study, mean daily temperature data from 34 geographical clustered weather stations representing all parts of Germany were analyzed. It is concluded that the increasing trend for average daily temperatures observed in the period from 1984 to 2013 has led to climatic conditions that allow the completion of dirofilarial life cycles in large parts of Germany between May and October. Autochthonous infection with D. repens is already established in some regions and targeted diagnosis and medical prophylaxis is advisable for dogs assumedly exposed during risk of transmission periods. It appears likely that global warming will support further spread of D. repens. Furthermore for the population of dogs the spread of the more pathogenic species D. immitis in hitherto non-endemic Germany is a potential risk if mean temperatures rise to a level suitable for parasite development in the abundant vector mosquitoes during the warmer seasons.

Gastrointestinal nematode infection interferes with experimental allergic airway inflammation but not atopic dermatitis.

BACKGROUND: Some helminth infections are negatively associated with the prevalence of allergic disorders, arguing for a modulation of allergic reactions by the parasites, depending on the worm species, intensity and phase of infection and the type of disease. OBJECTIVE: The aim of this study was to analyse the influence of a chronic infection with the gastrointestinal nematode Heligmosomoides polygyrus, in a murine model of allergic airway disease and of atopic dermatitis (AD), respectively. METHODS: Mice were infected with H. polygyrus and systemically sensitized with the model allergen ovalbumin. Subsequently, the animals were challenged with the allergen either via the airways for induction of airway disease, or via skin patches for induction of dermatitis. RESULTS: Mice concomitantly infected with H. polygyrus showed diminished eosinophil and lymphocyte recruitment into the lungs and decreased allergen-specific IgE levels when compared with sensitized and airway challenged controls. In addition, animals showed a trend towards reduced airway hyper-reactivity. In contrast, no significant differences in the severity of eczematous skin lesions were observed between infected and control animals in the AD model. Although H. polygyrus infection reduced CD8+ and CD4+ T-cell infiltration into the skin and production of allergen-specific IgE, mast cell recruitment was significantly increased in worm-infected mice in the dermatitis model. The worm infection was associated with significantly elevated numbers of Foxp3+ regulatory T cells (Treg) in peribronchial lymph nodes in H. polygyrus-infected sensitized and airway challenged mice. In contrast, Treg cells were basically absent in eczematous skin and their number was not increased in skin-draining lymph nodes of mice with experimental dermatitis. CONCLUSION: Infection with the gastrointestinal nematode used in our study leads to significant inhibition of mucosa-associated but not cutaneous allergic reactions, pointing to a site specificity of the immunomodulation exerted by helminths. This finding might be an important aspect for future considerations of helminths for treatment of allergic diseases.