Setaria digitatainfections in cattle: parasite load, microfilaraemia status and relationship to immune response

Abstract

A total of 110 cattle were examined in an area endemic for Bancroftian filariasis for the prevalence of infection of the bovine filarial parasite Setaria digitata. About 12.5% of cattle were found to harbour both adult worms in the peritoneum and microfilariae (mf) in circulation; 70% of the cattle were amicrofilaraemic but with an adult worm infection. A third group of cattle (16.5%) was free of detectable mf and adult worms. The presence of adult worms and/or mf did not influence the antibody levels to any of the four antigen preparations of S. digitata. However, there was a significant inverse relationship between the presence of antibodies to microfilarial sheaths and the absence of circulating mf as shown by the immunoperoxidase assay. Cattle immunoglobulin containing high titres of anti-sheath antibodies cleared circulating microfilariae very effectively in Mastomys coucha thus demonstrating the protective nature of anti-sheath antibodies in eliminating circulating microfilariae in vivo.

Occurrence of Setaria labiatopapillosa in peritoneal cavity of a crossbred cattle

“…So far as reports on the epidemiology of setarial worms is concerned, more reports are available on the prevalence of S. digitata in cattle as compared to S. labiatopapillosa (Shoho 1958;Mohan 1975;Patnaik 1989;Mohanty et al 2000;Tung et al 2003;Nakano et al 2007;Kim et al 2010). Further, only scanty published reports are available on the occurrence of S. labiatopapillosa amongst Indian cattle (Patnaik 1989;Sundar et al 2005) particularly Punjab state, from where only one published report of occurrence of S. labiatopapillosa in buffalo is on the record (Singh et al 1996).…”

Subconjunctival infestation with Setaria

“…This is unlike the cases of ocular loiasis, in which another nematode, Loa loa is the infective parasite, that require the antifilarial systemic medication (Khoramnia & Wegner, 2010). Symptoms appear mostly weeks or months after the infestation (Mohanty et al, 2000). In our case, the interval between the presumable infestation (in Singapore) and the onset of symptoms was of 2 years.…”

“…Cattle are the natural hosts of Setaria and are not greatly affected by the parasite (Mohanty et al, 2000). The vector (the mosquito Armigeres sp.)…”

“…rarely survives in the abnormal hosts and the microfilariae of Setaria spp. rarely can be identified in blood tests (Mohanty et al, 2000;Ahmad & Srivastava, 2007). The microfilariae of Setaria spp.…”

“…Because the mosquito Armigeres sp. has an antropophilic biting habit, a large proportion of humans are exposed to the infestation with Setaria spp., but the parasite does not go through its all lifecycle in humans (Mohanty et al, 2000). Surgical extraction is the treatment of choice and since the worm is unable to replicate itself in human, no systemic antiparasitic therapy is necessary.…”