Parasite density and malaria morbidity in the Pakistani Punjab

The relationship between quantitative Plasmodium falciparum or P. vivax par asitemia and clinical illness has not been defined in Pakistan or in other areas where malaria transmission is not highly endemic. Standardized questi onnaires were given to and physical examinations and parasitologic tests we re performed in 8,941 subjects seen in outpatient clinics in 4 villages for 13 consecutive months in the Punjab region of Pakistan. The results, based on multivariable analysis, showed that a clinical diagnosis of malaria, a history of fever, rigors, headache, myalgia, elevated temperature, and a pa lpable spleen among children were all strongly associated with the presence and density of P. falciparum or P. vivax malaria in a monotonic dose-respo nse fashion. The malaria attributable fraction of a clinical diagnosis of m alaria, and the same symptoms and signs also increased with increasing P. f alciparum and, to a lesser extent, P. vivax, parasitemia. Unlike in sub-Sah aran Africa, clinical illness due to malaria often occurs in the Punjab amo ng adolescents and adults and in patients with parasite densities less than 1,000/mu l. Clinical guidelines based upon parasitemia and symptomatology must be adjusted according to the intensity of transmission and be specific for each geographic area.