The relationship between the intensity of Gasterophilus intestinalis larvae infection and the serum and salivary humoral immune response in horses.

Infection with Gasterophilus intestinalis (botfly) larvae often occurs in horses. The aim of the study was to isolate the larvae of G. intestinalis and evaluate the serum and salivary humoral immune response using self-developed ELISA in G. intestinalis infected horses. Blood serum or saliva samples were taken from 125 infected horses and 54 uninfected slaughtered horses. The antigens from G. intestinalis larvae were used for development of ELISA in order to evaluate the intensity of G. intestinalis IgG, IgM, and IgA antibody reactivity in the serum or saliva of naturally infected horses and horses without larvae in the gastrointestinal tract (control group). Serum antibodies against second and third larvae's stadium antigens reacted significantly more intensively in infected than in healthy horses in IgG (p ≤ 0.001; p ≤ 0.05, respectively) and IgA (p ≤ 0.05;p ≤ 0.001, respectively) classes. Salivary IgG and IgA specific's antibody reactivity was significantly higher in horses with moderate (p ≤ 0.01) and severe infection (p ≤ 0.001) compared to the healthy horses. The determination of the G. intestinalis IgG and IgA antibody activity in saliva and serum may be used for detecting horses moderately and severely infested with larvae.

Molecular comparison of Gasterophilus intestinalis and Gasterophilus nasalis from two distinct areas of Poland and Italy based on cox1 sequence analysis.

In this study, Gasterophilus intestinalis and Gasterophilus nasalis collected from horses in northeastern Poland and southern Italy were genetically compared. The cox1 sequences of the Polish and Italian G. nasalis larvae revealed a higher degree of geographic genetic diversity, with an intra-specific variation rate of 1.27%, than the G. nasalis specimens collected in Poland (intra-specific variation rate: 0.49%) and those collected in Italy (intra-specific variation rate: 0.58%). However, the level of genetic homology of the Polish and Italian G. intestinalis specimens (intra-specific variation rate: 1.27%) was similar to that of the G. intestinalis larvae collected in northeastern Poland (intra-specific variation rate: 0.94%) and those collected in southern Italy (intra-specific variation rate: 1.16%). Analysis of the restriction enzyme sites in the coxI gene of G. nasalis and G. intestinalis showed that the nucleotide polymorphism (NP) at position 1050 of this gene determines cleavage by MnlI only in G. nasalis, making it possible to differentiate the two species using PCR-RFLP. Interestingly, comparison of the nucleotide sequences of the PCR-amplified coxI gene fragments from the Italian specimens of G. nasalis with other analyzed cox1 genes revealed an additional NP at position 1236 of cox1 gene, recognized by MnlI. The present study shows that G. nasalis specimens from different geographical areas display a level of genetic diversity which can influence PCR-RFLP analysis.