Gametocytemia and fever in human malaria infections

Abstract

We examine the charts of 408 malaria-naive neurosyphilis patients given malaria therapy at the South Carolina USPHS facility, with daily records encompassing at least 93% of the duration of infection, and focus on the 152 patients infected with the St. Elizabeth strain of Plasmodium vivax, 82 with the McLendon strain of Plasmodium filciparum, 36 with the USPHS strain of Plasmodium malariae, and 15 with the Donaldson strain of Plasmodium ovale in whom gametocytes appeared before drug, or other, intervention. In P. vivax infections, fever and parasitemia were higher after gametocytes were first detected than before; in P. malariae infections, parasitemia was higher. In P. ovale infections, fever and parasitemia were similar before and after. In P. falciparum infections, fever, parasitemia, and fever frequency were lower after gametocytes were first detected than before. Parasitemia and temperature correlated in P. vivax infections, before and after gametocytes were first detected; parasitemia and temperature at first fever were not correlated in infections with any species. Gametocyte density correlated with parasitemia in P. malariae and sporozoite-induced P. falciparum and P. vivax infections. Fevers and detected gametocytemia coincided more often than expected by chance with P. vivax and P. ovale; fever temperature and gametocyte density were not correlated in infections with any species.

Figure 1

Day-by-day frequencies (percentage of patients; vertical axis) of fever or gametocytemia, from the first day of patency (as day 1; horizontal axis). Top panels: P. falciparum, trophozoite-induced (left, A) and sporozoite-induced (right, B). Middle panels: P. vivax, trophozoite-induced (left, C) and sporozoite-induced (right, D). Bottom panels: P. malariae (left, E) and P. ovale (right, F), both trophozoite-induced.

Figure 2

Schematics of idealized P. falciparum (top panel) and P. vivax (bottom panel) infections. The first fever occurs on day a, the first gametocytemia on day b; day c is set such that interval bc = ab (group N3; see text).

Figure 3

The proportion of patients (%; vertical axis) in whom the median parasitemia or median fever before gametocytes were first detected was higher than the median after, in P. falciparum (FAL), P. vivax (VIV), P. malariae (MAL), and P. ovale (OVA) infections, induced by trophozoites (troph) or sporozoites (sporo), in the N2 or N2 + N3 patients (see text).