A comparison of counterimmunoelectrophoresis and indirect haemagglutination tests for the immunoepidemiological investigation of kala-azar.

Counterimmunoelectrophoresis (CIE) using cell-free extracts of Leishmania donovani promastigotes and Trypanosoma brucei as antigens and indirect haemagglutination (IHA) using commercially prepared reagents were compared for their diagnostic efficacy and applicability to immunoepidemiological studies in an area of Bangladesh where kala-azar is present. The CIE was positive for all parasitologically confirmed cases whereas the IHA positivity was only 60%. The T. brucei antigen was equally as good, if not better, than the L. donovani antigen for CIE. The CIE test was negative for all of 34 apparently healthy villagers. For this same group of individuals, 10 (29%) were low titre-IHA positive. The findings suggest that CIE is the more reliable diagnostic test but both methods should be employed for immunoepidemiological investigations.

ELISA antibodies to cysticerci of Taenia solium in human populations in New Guinea, Oceania, and Southeast Asia.

The presence of ELISA antibodies to cysticerci of Taenia solium was surveyed in populations of New Guinea, Micronesia, and several areas of Southeast Asia. It is confirmed that cysticercosis in New Guinea remains limited to the primary Wissel Lakes focus in Irian Jaya, where the disease was introduced by the importation of infected pigs, and that it has not spread to populations east or south of the Wissel Lakes, or to Papua New Guinea. On the island of Bali, Indonesia, 21% of sera were positive from one village where pigs are especially numerous, whereas in Sumatra, Indonesia, only 3%-4% of sera were positive. In Singapore, there was a higher proportion of positive sera among the Chinese (13%) than among the Indian (5%) or Malay (3%) Moslems. From 3 to 13% of sera from populations in Micronesia, Burma, Vietnam, and the Philippines were also found to react with cysticercus antigen. However, the problem of incomplete ELISA specificity raises the possibility that in areas not known to be endemic for T. solium, seropositive results could represent either subclinical infection with cysticerci or crossreactivity to other parasitic infections.

Observations on the application of counterimmunoelectrophoresis for the seroepidemiology of human cysticercosis.

An immunoepidemiological survey for cysticercosis was carried out in an endemic focus of Irian Jaya by use of a counterimmunoelectrophoresis (CIEP) technique. All individuals with palpable subcutaneous cysticerci were serologically positive by this technique as were 77.3% of the individuals giving a history of epileptiform seizures and 22.5% with no clinical complaints. The possible application of CIEP for epidemiological surveillance is discussed.

Studies on filariasis in the Pacific. 5. Brugia malayi filariasis in treated and untreated populations of South Borneo.

A blood survey employing membrane filter concentration (MFC) and examination of stained 20 c.mm thick blood films as diagnostic methods was carried out in Banjar Regency of South Borneo, an area of endemic B. malayi filariasis. In untreated populations the mf rate, as revealed by MFC, ranged from 23.2% for the 5-9 year old group to 43.7% for the greater than 50 year old group. For all age groups approximately one half of the microfilaraemias were of a low grade nature, diagnosed by MFC only. In a population that had been subjected to mass DEC administration 1 1/2 years prior to this survey, the MFC-diagnosed rate was 15%. Approximately two thirds of these infections were of very low density, the average density being 2.2 mf/ml.

Studies on filariasis in the Pacific. 4. The application of the membrane filter concentration technique to a survey of Wuchereria bancrofti filariasis in Kepu district, Jakarta, Indonesia.

A blood survey for filariasis was carried out in the Kepu District of Jakarta. Examination of stained 20 c.mm finger-prick blood thick films and membrane filter concentration (MFC) of 1 ml venous blood. The youngest age group examined, 5-9 years old revealed a mf rate of 17% of which 71% were of a low density character detected by MFC only. The mf rate appears to remain relatively constant from the 10-14 year old group onward, approximately 35%, but at all age groups at least half the infections were of low density. The highest mf rate and density was observed present in the 15-20 year old group.