Socio-demographic determinants of Toxoplasma gondii seroprevalence in migrant workers of Peninsular Malaysia.

BACKGROUND: The number of migrants working in Malaysia has increased sharply since the 1970's and there is concern that infectious diseases endemic in other (e.g. neighbouring) countries may be inadvertently imported. Compulsory medical screening prior to entering the workforce does not include parasitic infections such as toxoplasmosis. Therefore, this study aimed to evaluate the seroprevalence of T. gondii infection among migrant workers in Peninsular Malaysia by means of serosurveys conducted on a voluntary basis among low-skilled and semi-skilled workers from five working sectors, namely, manufacturing, food service, agriculture and plantation, construction and domestic work. METHODS: A total of 484 migrant workers originating from rural locations in neighbouring countries, namely, Indonesia (n = 247, 51.0%), Nepal (n = 99, 20.5%), Bangladesh (n = 72, 14.9%), India (n = 52, 10.7%) and Myanmar (n = 14, 2.9%) were included in this study. RESULTS: The overall seroprevalence of T. gondii was 57.4% (n = 278; 95% CI: 52.7-61.8%) with 52.9% (n = 256; 95% CI: 48.4-57.2%) seropositive for anti-Toxoplasma IgG only, 0.8% (n = 4; 95% CI: 0.2-1.7%) seropositive for anti-Toxoplasma IgM only and 3.7% (n = 18; 95% CI: 2.1-5.4%) seropositive with both IgG and IgM antibodies. All positive samples with both IgG and IgM antibodies showed high avidity (> 40%), suggesting latent infection. Age (being older than 45 years), Nepalese nationality, manufacturing occupation, and being a newcomer in Malaysia (excepting domestic work) were positively and statistically significantly associated with seroprevalence (P < 0.05). CONCLUSIONS: The results of this study suggest that better promotion of knowledge about parasite transmission is required for both migrant workers and permanent residents in Malaysia. Efforts should be made to encourage improved personal hygiene before consumption of food and fluids, thorough cooking of meat and better disposal of feline excreta from domestic pets.

Brugia malayi infection in Meriones unguiculatus: antibody response to recombinant BmR1.

BmR1 recombinant antigen has previously been shown to demonstrate high sensitivity and specificity in the serological diagnosis of brugian filariasis in humans. In this study, the pattern of recognition of antibody to BmR1 during Brugia malayi infection was investigated by employing Meriones unguiculatus as the experimental model. Thirty two gerbils were infected subcutaneously with 120 L(3); and two control groups each comprising 25 animals were employed. ELISA using BmR1 was used to detect filaria-specific IgG antibodies elicited by the gerbils; using sera collected from the day 1 until day 150 post-inoculation (p.i.). The results showed that BmR1 detected B. malayi infection in gerbils harboring adult worms irrespective of the presence of circulating microfilaria, and was exemplified by positive ELISA results in nine a microfilaraemic animals that harbored live adult worms. The initial time of the antibody recognition was at day 8 p.i. and the antibody titre showed some correlation with adult worm burden.

Toxoplasmosis in HIV/AIDS patients: a current situation.

The seroprevalence of toxoplasmosis among 505 of human immunodeficiency virus (HIV)/AIDS patients was 226 (44.8%; 95% CI 42.64-51.76): 27 (47.4%) and 199 (44.4%) showed Toxoplasma seropositivity with and without toxoplasmic encephalitis (TE), respectively (P <0.05). The majority of these patients were in the 25-34 age group (44 versus 39%), male (86 versus 76%), and Chinese (49 versus 53%), though no statistical significance was found between the two. Significant differences between these two groups were noted, however, in terms of marital status, occupation, and present address. The heterosexual exhibited the most frequent behavior at risk for HIV infection, and accounted for 51 and 59% of patients with and without TE, respectively. Only 17/260 (6.5%) and 1/137 (0.7%) of them later acquired TE after receiving primary chemoprophylaxis (cotrimoxazole) and antiretroviral therapy including HAART (P <0.05). Fifty-seven (11.3%) out of those 505 patients were diagnosed with AIDS-related TE. The most common clinical manifestation was headache (56%). The computed tomography scan findings showed most lesions to be multiple (96.4%), hypodense (66.7%), and in the parietal region (39.3%). Twenty-seven (47.4%) patients had chronic (latent) Toxoplasma infection as evidenced by seropositivity for anti-Toxoplasma (IgG) antibody. At the time of diagnosis, the range of CD4 cell count was from 0-239 with a median of 25 cells/cumm. We also found that a CD4 count of less than 100 cells/cumm was significantly associated with development of TE (P <0.05). Clinical outcomes showed that among those who survived, 21 (36.8%), 16 (28.1%), and 2 (3.5%) of patients had completed treatment, transferred out, and were lost to follow up, respectively. Unfortunately, 18 (31.6%) of the cases were officially pronounced dead. Overall, 7 (12.3%) patients were detected as recurrent TE in this study.

Review on human toxoplasmosis in Malaysia: the past, present and prospective future.

We reviewed various studies regarding human toxoplasmosis in Malaysia. They showed a varying prevalence of specific Toxoplasma antibodies among the Malaysian population. The Malays have shown the highest seroprevalence of toxoplasmosis, by most studies, when compared to other races. Demographic profiles have shown that Toxoplasma seropositivity is higher in males than females, lower in people with higher incomes, higher in the unemployed and tends to increase with age. In general, the route of transmission, such as contact with a cat, consumption of undercooked meat and blood transfusion were shown to have no significant association with Toxoplasma seropositivity (p > 0.05). The immune status (CD4 cell count < 200 cell/mm3) was strongly associated with toxoplasmic encephalitis (p < 0.05).

AIDS-related opportunistic infections in Hospital Kuala Lumpur.

We retrospectively reviewed 419 HIV/AIDS patients in Hospital Kuala Lumpur from 1994 to 2001. In the male group, the age range was 20-74, with a mean age 37 years, while in the female group it was 17-63, with a mean age of 33 years. With regard to age group, it was found that the preponderant age group was 25-34 years. The majority of male subjects were Chinese (52.5%), single (56.3%), and unemployed (55.1%), whereas the females were Malay (42.3%), married (79.5%), and non-laborer (64.1%). Also, both groups resided in Kuala Lumpur and had heterosexual contact as the leading cause of HIV transmission. More than half of the patients had CD4 cell counts of <200 cells/cumm. We found that the acquisition of HIV infection via intravenous drug use (IDU) was directly related to the incidence of tuberculosis infection (P < 0.05). Further analysis showed HIV-related tuberculosis with IDU was also dependently correlated with occupational status (unemployed) (P < 0.05). The four main AIDS-defining diseases include tuberculosis (48%), Pneumocystis carinii pneumonia (13%), toxoplasmic encephalitis (11%), and cryptococcal meningitis (7%); in addition, 53% of these patients were found to have CD4 cell counts of less than 200 cells/cumm at the time of diagnosis.

Tuberculosis in AIDS patients.

Tuberculosis is the top agenda among opportunistic diseases and the most leading cause of death in HIV/AIDS patients. A total of 406 AIDS patients were recruited in this retrospective and descriptive study. 123/406 (30.3%) were diagnosed as AIDS-related tuberculosis (TB). Their age range from 17 to 69 years with a mean (±SD) of 37.2 (±9.51. There were significant association between occupation, or mode of HIV transmission and tuberculosis infection (p< 0.05). Pulmonary tuberculosis 104/123 (84.6%) was the most common disease location among TB patients. We found the significant association between the clinical presentations i.e. fever, cough, sputum or hemoptysis and TB patients (p<0.05), moreover, the level of CD4 cell count plays a significant role in association with the disease (p<0.05) in this study.