[The malaria situation in the Russian Federation (1997-1999)]

Profound socio-economic changes within the CIS countries in the 1990s brought a lot of negative changes in malaria prevention in targeted countries. The previously stable connection and cooperation in prophylactic activities have been interrupted. Supply of antimalarials, insecticides and equipment had been stopped. Many qualified cadres in the sanitary-epidemiological services in the countries were lost. Because of difficult economic situation they had to change their occupation and place of job. After prolonged period of a stable benign epidemiological situation within Russia the number of imported cases started to grow up. The sharp increase of imported malaria cases from Azerbaijan and Tajikistan had been noticed since 1994 (Tab. 1). For the first time in the history of malaria registration the number of cases imported from the CIS countries has been exceeded the number of malaria cases imported from all other countries in the world in 1995. Later in the end of the 1990s the imported malaria cases has been registered in Russia from some other CIS countries apart from Azerbaijan and Tajikistan. There were malaria cases imported from Armenia (13 cases), Moldavia (2), Turkmenistan (2), and Uzbekistan (2) in 1998. The number of imported malaria cases in Russia in 1999 (Jan-July) is 437. There is no information about introduced or indigenous malaria cases registered until now] within Russia. There were 13 introduced malaria cases as the result of numerous imported ones. 13 introduced cases have been registered in 10 oblasts (administrative regions of Russia). This number has been increased to 53 (!) in 1998 in 20 oblasts. There was one local outbreak of P. vivax malaria in Izberbash settlement (Dagestan). Number of indigenous malaria cases were 5 (1996), 18 (1997), 1 (1998). The contra-epidemic measures in Izberbash have included active cases detection and treatment indoor insecticide spaying and one tour of mass primaguine treatment during interseasonal period of time. Additional indigenous cases after imported and introduced ones have been detected in Krasnodar (1 cases), Samara (1), Tolyaty (1), and Cherkessk (5) in 1998. One induced P. falciparum malaria case has been detected Moscow in 1998. Medical nurse from urological branch of the Moscow hospital No. 29 has penetrated by syringe needle her hand after performing of intravenous injection to the patient with imported P. falciparum malaria. No other induced cases have been detected. Because of local administrative problems with primaquine supply not all P. vivax malaria cases have received complete treatment. As the result of these events there was malaria relapsed cases registered every year. The actual number was 20 (1993), 37 (1994), 45 (1995), 59 (1996), 99 (1997). Due to late appearance of patient with P. falciparum malaria before medical staff and as a result late diagnosis and late and some time inappropriate treatment there were several lethal malaria cases registered [table: see text] every year. Inappropriate treatment means that treatment of P. falciparum malaria cases was consisted of chloroquine only. The cumulative number of lethal cases in 1994-1997 was 12, and the same number in 1998 was 6. One should mention that one lethal case in 1998 in Volgograd was due to P. vivax. The subject was chronic alcoholic and combination with P. vivax malaria brings him to death. Some calculation reveals the risk of resurgence of malaria in Russia. If one analyses all P. vivax imported cases from the point of view of time and place of detection the following picture would be emerged: 83% of all imported cases has been localized within cities, and 17% only--in rural areas. Half of the latter has been appeared during cold part of years when transmission was impossible. The result of approximately 200 imported cases has been appeared in a right time and place there were 75 introduced cases.

[Changes in the manifestations of tertian malaria on the territory of the CIS Nations]

The investigations made in the areas of residual endemics and the retrospective analysis of the prevalence of vivax-malaria revealed changes in its manifestations and in the functioning of parasitic systems in the past decades: selection of P. vivax strains with long-term incubation in the southern areas of the CIS and in the north of Afghanistan, which constitute a northern world areal boundary, increases in the periods of late manifestations up to 30-38 months, the minimal risk of renewal and implanting of malaria transmission in malarious territories where it was eradicated in the 1950s. The change in the habitance stimulates self-regulation for effective adaptation and species preservation. The pronounced adaptative properties of P. vivax which manifested themselves in altered changes of signs of vivax-malaria with short- and long-term incubations in the CIS should be borne in mind while planning and launching antimalarial measures in the endemic areas. These data may be useful in the comparative characterization of malarial parasitic systems in its various areas of spread.

[A method for stratifying malariogenic territories in order to construct a system of mathematical models of the prevalence of malaria. 1]

The paper describes procedures for stratifying malariogenic areas that are homogeneous in the development pattern for epidemic stratum rises, which will be used to design a set of mathematical malaria spread models. The first stage of the procedures is to stratify P. falciparum and P. vivax malaria on phase planes. The morbidity rate of P. falciparum and P. vivax malaria was analyzed in the north-western areas of India in 1975-1990. Eighty-two observations provided 4 types of phase curves for tropic malaria, which form a polygon, a loop polygon, U-shaped ones and those without any specific signs and 4 groups of phase curves for P. vivax malaria and the U-shaped phase curve with a loop for P. vivax malaria. It is shown that there is a steady-state pattern of phase curve changes in 71%. It is suggested that the pattern of a phase curve can be a diagnostic characterization of the given area.

Importation of malaria into the USSR from Afghanistan, 1981-89

Between 1981 and 1989, a total of 7683 cases of Plasmodium vivax [corrected] malaria were imported into the USSR from Afghanistan, mainly by demobilized military personnel. For 23.8% of these cases the clinical manifestations appeared within a month of returning to the USSR, for 22.5% after 1-3 months, for 20% after 4-6 months, for 2% after > 1 year, and for 0.6% after > 2 years. For 13 patients the clinical manifestations of malaria appeared 3 years after returning from Afghanistan (up to 38 months). Nearly 69% of the patients did not take malaria prophylaxis at all while they were in Afghanistan, and 19% took chloroquine irregularly. Only 12.5% of the patients received a full course of prophylactic treatment with primaquine before leaving Afghanistan. A total of 56% of the cases were detected during the period most favourable for malaria transmission in the USSR (May-September) and of these, half were imported into formerly malarious areas of the country. Activation of a surveillance system greatly reduced the consequences of the massive importation of malaria, to which the local vectors were susceptible.

[The importation of malaria from Afghanistan into the USSR (a retrospective analysis of data from epidemiological surveys of cases and foci during 1981-1990)]

A retrospective analysis of imported malaria due to military operations revealed the main regularities in the behaviour of Plasmodium vivax population and the relationships between the imported parasite and the native Anopheles species. High percentage of cases with protracted incubation was noted in soldiers after their home-coming; the clinical symptoms were often registered 7-12 months after return. No epidemic consequence of imported and introduced cases of tertian malaria in malariogenic areas was shown. The effect of mass drug administration in military contingents was proved to be low due to irregular use of drugs or their discontinuance. The import of carriers to malariogenic areas was found to cause a minimal risk of restoration and implantation of tertian malaria. The current epidemiological monitoring system was shown to be rather effective for maintaining the epidemiological prosperity in the country.