Detection of filarial antibodies in Malayan and Bancroftian filariasis by the indirect fluorescent antibody test, using different filarial antigens.

Indirect fluorescent antibody tests (IFAT) using Wuchereria bancrofti infective larvae as antigen had the highest positivity rates in detecting Malayan and Bancroftian filariasis as compared to IFAT using antigens prepared from 5 other animal filarial species, Brugia pahangi, Dirofilaria immitis, Dipetalonema viteae, Litomosoides carinii and Onchocerca gutturosa. This study also recommends the use of human filarioids as the source of antigen in serological tests. However, before B. malayi and especially W. bancrofti can be easily available from the common laboratory animals. B. pahangi seems to be a suitable source of antigen for use in serological tests for human lymphatic filariasis.

Detection of circulating antigens and immune complexes in feline and human lymphatic filariasis.

Circulating worm antigens were detected in 61% to 81% of sera from Brugia pahangi -infected cats and in 0-93% of sera from humans with malayan of bancroftian filariasis by counter immunoelectrophoresis and a double antibody sandwich enzyme-linked immunosorbent assay, using rabbit antisera to B. pahangi adult worms. In some situations, both antigen tests were as sensitive as antibody tests. However, ELISA was likely to be affected by the presence of antiglobulins, such as rheumatoid factor, in the test sera. Only 10% to 22% of B. pahangi-infected cats (treated with drugs or not) had circulating immune complexes by the conglutinin-binding assay and no sera were positive by C1q-BA. A significantly higher percentage (56%) of B. malayi clinical sera was positive for immune complexes by either C1q- or conglutinin- binding assays as compared to other groups of B. malayi and Wuchereria bancrofti sera (6% to 14%).

A comparison of the efficiency of the Nuclepore and Millipore filtration systems for detecting microfilariae.

Using Brugia pahangi or Dirofilaria immitis as the test organisms no significant difference could be detected between Nuclepore and Millipore filters. It was found that 0.7% of microfilariae passed through the Millipore and 1% through the Nuclepore filters. No microfilariae were lost from the Nuclepore membrane during the staining process.

Studies with Brugia pahangi. 11. Measurement of lymph flow in infected cats.

Rates of lymph flow in cats were measured by calculating the disappearance of radioactive colloidal gold (198Au) from the feet of (1) uninfected cats, (2) cats infected for various periods after primary infection with Brugia pahangi, and (3) cats repeatedly challenged with B. pahangi infective larvae over long periods. The results of the study showed that (1) there is great variation in gold disappearance rates in different cats in all 3 groups above, (2) the cat lymphatic system is functionally highly efficient, and (3) in a cat with lymphoedema and early elephantiasis, there was a significant impairment of gold removal from the affected foot. The study proved useful in finding lymph drainage rates in the various animals but did not, as hoped, show any pattern of lymph flow decrease which might have enabled the use of the technique as a diagnostic tool for lymphatic pathology prior to the occurrence of external clinical manifestations of filariasis.