Naegleria fowleri in Thailand, 2003

Abstract

Between 1988 and 2003, Naegleria fowleri was studied extensively in Thailand. The distribution of N. fowleri has been studied in many provinces since 1988. During 2001-2003, we received financial support from Mahidol University to study the distribution of pathogenic Naegleria spp in water reservoirs in central, northern, and western parts of Thailand. With these funds, research was conducted in Bangkok (Taling Chan District), Saraburi, Nakhon Nayok, Nakhon Sawan, Sukhothai, Prachuap Khiri Khan, Surat Thani and Chumphon Provinces. Studies indicated that pathogenic strains of Naegleria belonging to the species fowleri were found in Saraburi and Surat Thani, and could be identified by external morphology, molecular weight, isoenzyme patterns and cytopathogenicity. However, the development of therapeutic drug treatment is still problematic because of the high mortality rate and rapid progression of disease. Since 1970, the effects of numerous drugs and chemical agents have been studied; there are continuing efforts to develop new drugs in vitro and in vivo, because the current treatment of primary amebic meningoencephalitis remains ineffective for most patients. A study of the in vitro effect of various antifungal drugs and the drug combination 5-fluorouracil and amphotericin B on pathogenic Naegleria spp was published in 2002. In was concluded that amphotericin B, in combination with 5-fluorouracil was still the most effective treatment for pathogenic Naegleria spp infection. In addition, the IC50of this drug combination was significantly lower than that of amphotericin B and 5-fluorouracil alone. Moreover, this drug combination has high synergistic activity and few side-effects in patients. These results emphasize the need for prompt treatment at an adequate minimum dosage by intrathecal route to arrest the disease.