Malaria Clinical Studies
Basic Sciences  | Muriithi-Wellde CRC  | Malaria Vaccine Trials | Malaria Drug Study | Previous & Proposed studies

Malaria Transmission

Since the early 1980’s studies on the epidemiology of malaria, transmission and pathogenesis, as well as testing of experimental malaria vaccines (R32LR Tox A, SPF66, RTS,S & MSP-1) and drugs (primaquine, azithromycin, atovaquone/proguanil, & tafenoquine) have been conducted in western Kenya. In addition to the malaria product development programs, other studies at the site center upon basic malarial pathophysiology (blood groups & cytokines as related to severe malaria & malarial anemia), emerging infectious diseases (diarrhea, fever & outbreak response as well as arbovirus, influenza & rift valley fever surveillance), and entomology (sandfly control, mosquito EIR, etc). In addition, a “Center of Excellence” program trains and refreshes both visiting and resident microscopists and lab technicians in advanced techniques of malaria slide diagnosis on a biannual basis.

Malaria transmission occurs all year but is maximal during the two rainy seasons.  A longitudinal epidemiological study conducted in 2003-2004 in Kombewa indicated that monthly attack rates range from approximately 20% to 55% in children aged 1 to 3 years in the proposed study area (Figure 1).  P. falciparum is present in over 90% of malaria cases. P. ovale and P. malariae, which together constitute less than 10% of cases, are usually present in mixed infections with P. falciparum.

The majority of the adult population gets malaria multiple times each year and is considered semi-immune.  Though the prevalence of malaria is high only about 25% of infected adults become symptomatic.

Figure1 Malaria Attack Rates in Kombewa Division 2003-2004 (EPI study of 270 Children age 1-3 years)