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Plasmodium falciparum histidine rich protein-2 (PfHRP-2) based immunochromatographic test kit (ICT Malaria Pf) for the rapid diagnosis of P. falciparum malaria was evaluated at the clinic of Malaria Research Centre (Field Station), Goa. Of the 98 febrile patients screened, 22 were ICT positive for P. falciparum. Simultaneous microscopic examination of the blood smears of these ICT positive patients showed that 20 were positive for P. falciparum alone, whereas one had mix infection of both P. vivax and P. falciparum suggesting 100% sensitivity. Only one slide negative patient who had taken 600 mg chloroquine the previous day was positive in the ICT. Out of the remaining 76 blood smears, 41 showed P. vivax infection and none cross-reacted with P. falciparum HRP-2 antigen and were ICT negative except one mix infection case in which P. vivax and P. falciparum infections occurred concomitantly suggesting species specificity of 98.7%. The positive predictive value, negative predictive value and efficacy of the ICT were 95.4, 100 and 98.9% respectively. The band intensity of the ICT positive cases significantly correlated with P. falciparum parasitaemia (p < 0.01). The usefulness and the disadvantages of this diagnostic kit have been discussed in context of prevailing malaria situation in the country.

Adult and larval insecticidal tests conducted in Panaji, Goa, revealed that adults of An. stephensi were resistant to DDT (4.0%), dieldrin (0.4%) and malathion (5.0%). The larvae of An. stephensi were also resistant to DDT (2.5 mg/l) and malathion (3.125 mg/l). Cx. quinquefasciatus adults were resistant to DDT, dieldrin, malathion and fenitrothion (1.0%), and larvae were highly resistant to DDT but showed low resistance to malathion and fenitrothion (0.125 mg/I). Adults of Ae. aegypti were resistant to DDT and dieldrin and the larvae showed resistance to DDT but good susceptibility to fenitrothion and complete susceptibility to malathion. The triple resistance of An. stephensi to DDT, dieldrin and malathion is intriguing as malathion has never been used in the health sector in Goa. A very limited use of malathion was done in the agricultural sector in Chandor area, which is 50 km away from the study area.

A one-year longitudinal study conducted in 9 categories of breeding habitats in Panaji, Goa, showed that 1.1% of the 67,360 breeding sites contained Anopheles stephensi immatures and the overall positivity varied from 0.4 to 3.5% with a peak in June. The habitat-wise proportion of An. stephensi was: wells, 0-1.3%; fountains, 1.4-11.4%; masonry tanks, 0.8-6.1%; overhead tanks, 0.1-4.0%; curing water in construction sites, 0.6-9.0%; groundwater tanks, 0-1.4%; tyres, 0-8.9%; barrels and tins, 0-5.4%; and intradomestic containers, 0-1.9%. An. stephensi was breeding along with An. subpictus, An. vagus, An. barbirostris, Culex quinquefasciatus, Cx. vishnui, Ae. aegypti, Ae. albopictus and Ae. vittatus.

A marked difference in malaria incidence amongst labour imported for construction and local residents was observed in a study following the outbreak of malaria in Panaji (Goa) in 1986. Water stagnation in and around the construction was the main breeding site for An. stephensi and the intensity of malaria transmission was dependent on the area under construction.