Successful treatment of Brugia pahangi in naturally infected cats with ivermectin

Filariasis of the breast caused by Brugia pahangi: A concomitant finding with invasive ductal carcinoma

Extralymphatic filariasis is an uncommon phenomenon that can be caused by several lymphatic filarial species, including zoonotic filaria of animal origins. In this study, we report a case of a 64-year-old Thai woman who presented with a lump in her left breast that was diagnosed with invasive ductal carcinoma. At the same time, a small nodule was found in her right breast, via imaging study, without any abnormal symptoms. A core needle biopsy of the right breast nodule revealed a filarial-like nematode compatible with the adult stage of Brugia sp. A molecular identification of the nematode partial mt 12rRNA gene and ITS1 suggested the causative species as closely related to Brugia pahangi, a zoonotic lymphatic filaria of animals such as cats and dogs. The sequence of the partial mt 12rRNA and ITS1 gene in this patient was 94% and 99% identical to the previously reported sequence of mt 12rRNA and ITS1 genes of B. pahangi. The sequence of ITS1 gene is 99% similar to B. pahangi microfilaria from infected dogs in Bangkok, which was highly suspected of having a zoonotic origin. As far as we know, this is the first case report of B. pahangi filariasis presented with a breast mass concomitantly found in a patient with invasive ductal carcinoma. This raised serious concern regarding the zoonotic transmission of filariasis from natural animal reservoirs.

Comparison of efficacy of ivermectin and diethylcarbamazine against naturally infected Brugia malayi microfilaria in dogs

Filarial parasites like Brugia pahangi and Brugia malayi can infect dogs. Adults of Brugia genus resides in the lymphatic system and microfilariae, in blood. There are increasing reports of detection of B. malayi microfilariae in dogs. A study was undertaken to compare the efficacy of repeated oral dosing of ivermectin (IVT) and diethylcarbamazine (DEC), individually and in combination against naturally infected B. malayi microfilariae in dogs. The species of the microfilariae was confirmed by acid phosphatase staining and polymerase chain reaction. The three treatment groups were 200 mcg/kg body weight IVT daily for 14 days (I), 6.6 mg/kg body weight DEC daily for 14 days (II) and IVT and DEC together in the same dose for a period of 5 days (III). Microfilarial status of the peripheral blood was assessed on the 0th, 7th, 14th and 21st day. Haematological parameters were measured on day zero and on the 21st day. Though, all the three treatment groups showed a reduction in the microfilarial concentration through the study period, complete absence of detectable microfilaremia was not noticed in any of the three groups by 21st day. Among the haematological parameters, statistically significant difference was observed in the post-treatment means of haemoglobin levels of group III when compared with group II. Since group III regime (IVT + DEC) was shorter and just as effective as the longer ones, it is considered superior to the other two.