Hematologic and Clinical Indices of Malaria in a Semi-Immune Population of Western Thailand

Abstract

This study examines hematologic profiles of persons with acute Plasmodium falciparum or P. vivax infection in Maesod on Thailand's western border with Myanmar compared with febrile, non-parasitemic persons also reporting to malaria clinics. Nine hundred seventy-nine subjects were malaria-negative, 414 were infected with P. falciparum, and 646 were infected with P. vivax. Persons with patent parasitemia tended to have significantly lower white blood cell, red blood cell, platelet, and hemoglobin levels than those who were malaria-negative. For the first time, a parallel trend in thrombocytopenia with parasitemia was found to be associated with both P. falciparum, and P. vivax infection. Using logistic regression, persons with platelet counts < 150,000/microL were 12-15 times more likely to have malaria than persons with platelet counts > or = 150,000/microL. This study supplements previous literature on the hematologic effects of malaria and helps define those alterations for a semi-immune population. Thrombocytopenia is identified as a key indicator of malaria in these febrile patients.

Gametocytemia in Plasmodium Vivax and Plasmodium Falciparum Infections

“…In previous work, we reported differences between male and female participants that produce bimodal distributions in the patient populations (Erhart et al, 2004). The results shown here combine the sexes, but they also hold when the comparisons are made strictly among men or among women, with one exception.…”

“…Because differences between the Coulter and QBC systems may have confounded analyses of reported densities , we did not pursue comparisons between sites. Detailed hematologic data were collected only in 2001 (Erhart et al, 2004). We used the Mann-Whitney U-test and Spearman's rank correlation coefficient to compare distributions (Sokal and Rohlf 1981), and give P values for 2-tailed tests.…”

“…Data were collected during studies of malaria rapid diagnostic devices, for which the methods are fully described elsewhere (Forney et al, 2001(Forney et al, , 2003McKenzie et al, 2003McKenzie et al, , 2005McKenzie et al, , 2006Erhart et al, 2004;O'Meara et al, 2005). Briefly, participants presented on their own initiative to existing outpatient malaria clinics operated by local public health authorities at Maesod, Tak Province, Thailand, or Iquitos, Peru, 28 May-28 August 1998 or 17 May-9 July 1999 (age ≥15 yr, Thailand; or ≥1 yr, Peru), with fever (oral temperature ≥38 C), headache, or selfreported history of fever within the previous 72 hr.…”

Study of haematological parameters in malaria

“…In studies conducted by Erhart LM et al, Jadhav UM et al, vivax was the most common species while Bashawri LAM et al reported higher falciparum prevalence. 3,16,17 In India, vivax is the most common species encountered followed by falciparum. However, in recent years there has been an upswing in the falciparum cases.…”

“…3,16,17 Thrombocytopenia is a common finding in cases of malaria both vivax and falciparum as shown by most of the studies conducted. In the present study thrombocytopenia was seen in 71% of all malaria cases.…”