[The results of serological studies in different foci of tropical and tertiary malaria]. / Rezul'taty serologicheskikh issledovanii v raznykh ochagakh tropicheskoi i trekhdnevnoi maliarii.

Attempt was made to determine the value of serologic indices of malaria surveys. Following uniformed methodological and technical approaches 3 foci of P. vivax and 6 foci of P. falciparum malaria were surveyed in different endemic zones of Vietnam and the USSR. It was shown that the most objective criteria for a foci classification is its serologic mean geometric titre. The latter in its turn directly depends of transmission longevity in a foci.

[Malaria morbidity among the nonimmune foreigners in the city of Maputo and the problem of chemoprophylaxis]. / Zabolevaemost' maliariei sredi neimmmunnykh inostrantsev v g. Maputu i problema khimioprofilaktiki.

In a colony with nonimmune foreigners in Maputo city (Mozambique People's Republic) active detection and treatment of patients suffering from malaria has been carried out for 1.5 years. It was shown that even in a city with some hyper- and mesoendemic regions where less than 10% of colony members were treated with chemoprophylaxis, yearly morbidity among them did not surpass 20-30 cases per 1000 population. Such index is considered to be admissible risk for health if adequate diagnosis and treatment of infection is available. Despite predominance of drug-resistant strains of tropical malaria agents among the local population, resistance to chlorochin or phancidar was observed in 3 foreign patients out of 31. In one case the clinical pattern of infection was atypical.

The Plasmodium falciparum chloroquine in vivo test: extended follow-up is more important than parasite counting.

349 in vivo tests of the susceptibility of Plasmodium falciparum to chloroquine, 25 mg/kg, were analysed. In some surveys, standard in vitro tests were also carried out. The proportions of sensitive and resistant infections in different areas found by the 2 methods were similar, but, within a given area, correlation between the two methods was often poor. Two RI cases and one RII/RIII case were sensitive in vitro, and it is suggested that the extended in vivo test may sometimes be more sensitive than the in vitro test, and that even in endemic areas, where reinfection is possible, patency on day 14 will nearly always be due to resistance. Parasite density data were analysed by calculating the geometric mean of each day's parasite density as a percentage of the day 0 parasite density + 0.1. Most resistant and sensitive infections attained minimal values on day 4, and it is proposed that assessment of sensitivity based on parasite densities should use day 4 values. Contrasts between materials were more clearly defined statistically when comparisons were based on ranking in vivo test classifications, than when based on day 4 parasitaemia. It is therefore suggested that, for epidemiological purposes, extension of tests to at least 14 d is more important than parasite counting. Parasitaemia above 20-25% of the day 0 value on day 2 in a severely ill patient, or persistent patency on day 4 in a symptomatic patient, are both indications for a change of treatment.

Plasmodium falciparum in vitro schizont maturation tests in Mozambique are not improved by removing immune parasite carriers' plasma.

To study the effect of immune parasite carriers' plasma on Plasmodium falciparum schizont maturation, peripheral blood stages were incubated for 24-40 h in RPMI medium with either 5% carrier's plasma + 5% non-immune AB serum or 10% non-immune serum. The number of schizonts per 200 asexual P. falciparum was lower in non-immune serum than in the presence of carrier's plasma in 19 of 26 cases, due to increased frequency of schizont rupture when carrier's plasma was absent. It is concluded that, under these test conditions, the replacement of immune plasma by non-immune serum makes schizont maturation tests, which are based on the proportion of schizonts among asexual P. falciparum as a measure of growth, more difficult to interpret.