ABSTRACT
Naegleria fowleri a free-living amoeba commonly found in moist soil and fresh water, enters the body via the nasal mucosa and migrates along the olfactory nerve to the brain, where it causes fulminant meningoencephalitis that is generally fatal. From 1988 to 1992, a survey of pathogenic Naegleria sp. was carried out in the industrial areas of three provinces. Water samples from warm and fresh ponds were collected from Pathumthani (34 samples), Samutprakan (150 samples) and Lopburi (162 samples). AII specimens were cultured in non-nutrient agar Escherichia coli media (NNE) AT 37oC. The amoebae obtained from water samples were in amoeboid, flagellate and cyst form. The amoeboflagellate transformation was occurred in distilled water and amoebae saline. The amoebae from water samples in Pathumthain (70.59 per cent) and Samutprakan (69.30 per cent) were cultured in Chang’s axenic media (SCGYEM) at 37oC. Non-pathogenic and pathogenic Naeglenia sp were distinguished by the characteristics of growth properties since the pathogenic form can grow only in the SCGYEM axenic media. The percentage of amoebae from Pathumthani and Samutprakan in SCGYEM axenic media at 37oC. were 11.46% and 12.00% respectively. The amoebae from Lopburi cultured in NNE 45oC (10.49 per cent) was inoculated through nasal cavity of Rattus rattus. The result was 10.49 per cent of the amoebae also determined for the virulence and the rats were died in 5-7 days. The histological studies of mouse brain tissue sections revealed the large central karysome and halo around the nucleus of the organisms, the amount of amoebae were accumulated around perivascular space. The characteristics, pathogenicity and pathology of pathogenic Naegleria sp. are the same as Naegleria fowleri.
ABSTRACT
A retrospective study was carried out on 15,396 samples at the Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University from January 1991 to December 1995. A total of 2,812 were found to have had parasitic infestation. Ages ranging from eight months to ninety-seven years old were recorded. The laboratories investigations including a simple saline smear, the sedimentation technique and special stains. The results were divided into four groups e.g., pathogenic protozoa (45.62%), nematode (40.36%); cestode and trematode. (8.67%) and non-pathogenic protozoa (5.33%) respectively. Pathogenic protozoan group comprised intestinal protozoa, blood and tissue sporozoa which were Blastocystis hominis (35.16%), Giardia lamblia (8.12%), Entamoeba histolytica (1.13%), Cryptosporidium sp. (0.90%), Plasmodium spp. (0.76%), Pneumocystis carinii (0.41%), Dientamoeba fragelis (0.22%) and Isospora belli (0.08%). The non pathogenic intestinal protozoa were Trichomonas hominess (2.80%), Entomoeba coli (2.51%), Endolimex nana (0.12%) and Iodamoeba buetschlii (0.02%). The intestinal nematode were found in the following percentages e.g., hookworms (20.43%), Strongyloides stercoralis (16.80%), Trichuris trichiura (0.61%), Ascaris lumbricolides (0.48%), Enterobius vermicularis (0.63%), and Capillaria philippinensis (0.12%). Angiosrongylus cantonensis was also observed in one case. The group was intestinal trematodes and cestodes consisted of Opisthorchis viverrini (6.02%), Taenia spp. (2.17%), Fasiola spp. (0.36%), Hymenolepis nana (0.12%).