ABSTRACT
The present study reports the characteristics of the 5S rRNA spacer sequences of Dirofilaria repens microfilariae isolated from dogs. The 22 nucleotide long spliced leader 1 sequences located in the 5S rRNA spacer region are completely conserved in all nematodes. There is variation in the spliced leader 1 sequences and associated sites in the 5S rRNA spacer region of D. repens. Absence of canonical SL 1 sequences distinguishes D. repens from other filarial species.
ABSTRACT
Identification of filarial species in dogs is clinically important because of zoonotic concerns and therapeutic implications. The present study was carried out to identify the filarial parasites causing microfilaraemia in dogs in Thrissur District, Kerala- an endemic area for human Brugian filariasis. Out of the 1600 dogs screened by wet blood film examination, 130 were positive for microfilariasis. Giemsa staining of blood smears revealed that 90 out of 130 dogs had unsheathed microfilariae, 24 had sheathed microfilariae and 16 had combined infection of sheathed and unsheathed microfilariae. Results of micrometry and histochemical staining of the sheathed microfilariae were in conformity with that of Brugia malayi. The DNA isolated from the sheathed microfilariae amplified the primers specific for the Hha 1 repeats of the B. malayi. Cloning and sequencing revealed that the amplified fragment corresponded to the 140-292 base pairs of the 320 base pair Hha1 repeat of Brugia malayi. The amplified DNA fragment also contained restriction sites for Alu 1 and Rsa 1which confirmed that the present isolate is Brugia malayi. The present study confirmed the presence of B. malayi in dogs in Kerala, India.
ABSTRACT
Brugia malayi is a filarial parasite that causes lymphatic filariasis in human beings. Kerala (India) is endemic for human Brugian filariasis. B. malayi microfilariae, similar to that causing filariasis in human beings, have been identified in dogs in Kerala. This is the first report of western blotting analysis of canine B. malayi microfilarial proteins. SDS PAGE analysis of B. malayi microfilarial protein revealed 5 major protein bands with molecular weights of 125, 80, 64, 54 and 27 kDa. Among these, the prominent bands were those having molecular weights of 64, 54 and 27 kDa. We raised polyclonal antibodies against these somatic proteins of dog microfilariae in a rabbit. The polyclonal antibodies recognized predominantly the 54 kDa and 64 kDa antigens in a Western blot analysis. Based on previous publications with B. malayi, these two protein bands appear to be important for diagnosis and for vaccine development against lymphatic filariasis.