Changing scenario of malaria in central India, the replacement of Plasmodium vivax by Plasmodium falciparum (1986-2000).
OBJECTIVE
Since 1986, we have been studying the changing epidemiology of malaria in a forest belt of Mandla, which has the highest number of malaria cases in central India (Madhya Pradesh) to define the epidemiological characteristics of the infection with each Plasmodium species in different seasons of the year. Our long-term objective was to determine the dynamics of Plasmodium vivax vs.P. falciparum infections.


METHODS
Five villages underwent fortnightly surveillance of fever cases. Drugs were distributed within 24 h after results of blood smears became available as per Indian National Anti-Malaria Programme. Indoor resting mosquitoes were also collected fortnightly.


RESULTS
The only two Plasmodium species encountered were P. vivax and P. falciparum in both children and adults. Relatively more malaria infections were recorded in children (< or =14 years) than adults (>14 years) (chi2=89.94, P<0.00001). However, there were significant falling trends in P. vivax from 1986 to 2000 in both age groups (< or =14 years from 63 to 13, P<0.0001 and >14 years from 84 to 7, P<0.0001). The indoor resting density of Anopheles culicifacies, an efficient vector resistant to both dichlorodiphenyltrichloroethane (DDT) (4%) and hexachlorocyclohexane (HCH) (0.4%), was very high throughout this period in all villages (52.35 +/- 31.8, range 5-200 per man hour). Anopheles fluviatilis was present in small numbers 0.78 +/- 1.24 (range 0-7 per man hour).


CONCLUSIONS
Major contributors of the changing epidemiology of malaria in this area are changing drug sensitivity along with insecticide sensitivity.
Malaria Research Centre, Jabalpur, India. oicmrc@yahoo.co.in
Neeru
N
Singh
A C
AC
Nagpal
Ajay
A
Saxena
M P
MP
Singh
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000818:Animals; D000852:Anopheles / Q000187:drug effects; D002648:Child; D002675:Child, Preschool; D004351:Drug Resistance; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D007223:Infant; D007303:Insect Vectors / Q000187:drug effects; D007306:Insecticides / Q000494:pharmacology; D016778:Malaria, Falciparum / Q000453:epidemiology*; D016780:Malaria, Vivax / Q000453:epidemiology*; D008297:Male; D011159:Population Surveillance / Q000379:methods; D015995:Prevalence; D012423:Rural Health
D007306:Insecticides