S eroprevalence of toxoplasmosis and associated risk factors among migrant workers in Malaysia

1. Seroprevalence of toxoplasmosis and associated risk factors among migrant workers in Malaysia ASSOC. PROF. DR. SITI NURSHEENA MOHD ZAIN Institute of Biological Sciences, Faculty of Science, University of Malaya. nsheena@um.edu.my

2. Introduction • The International Labor Organization (ILO) estimates that there are approximately 232 million international migrant workers worldwide. • Millions of migrants travelling to major urban cities around the globe to join the expanding workforces. Source: Temporary Work Visit Pass (PLKS), Immigration Department (Ministry of Home Affairs)

3. Toxoplasma gondii causes toxoplasmosis is one of the most common protozoan infection. • Affecting up to one-third of the world's population Source: CDC • There are various ways human may be infected including: • via ingestion of food or water that is contaminated with oocysts • consumption of unwashed raw fruits and vegetables • exposure to contaminated soil especially in children playing in sandpits • blood transfusion or organ transplantation • vertical transmission

4. Figure: Worldwide distribution of Toxoplasma infections Source: Pappas et al., 2009 • Dark red = above 60% • Light red= 40-60% • Yellow = 20- 40% • Blue = 10-20% • Green = <10% • White = No data.

5. The previous Malaysian study on toxoplasmosis were among 336 Indonesian migrant workers from plantation and detention camps (Chan et al., 2009). • 138 workers (42%) were found positive for IgG • 20 workers (6%) were positive for IgM. Despite compulsory medical screening for workers prior to entering the workforce, parasitic infections screening including toxoplasmosis is excluded. Therefore, there is an acute need for a more accurate understanding of the current status and epidemiology of toxoplasmosis in Peninsular Malaysia.

6. Methodology Approximately 5ml of venous blood were drawn and the sera were kept in -20°C until use. Research Ethics Reference number: MECID NO: 20143-40 Toxoplasmosis was screened using ELISA commercial kit for immunoglobulin G (IgG) and M (IgM) (The Trinity Biotech CaptiaTM, New York) • Positive IgG = indicating latent or pre-existing Toxoplasma infection. • Positive IgM = indicating recently acquired Toxoplasma infection. • IgG-positive and IgM-positive then tested with IgG avidity assay: • High avidity (>40%) indicates past infection. • Low avidity (≤40) indicates acute or recent infections.

7. Results and discussion • Toxoplasmosis positive: 279/485 (57.5%) were seropositive: • 53.0% (n= 257) positive for anti-ToxoplasmaIgG • 0.8% (n= 4) positive for anti-ToxoplasmaIgM • 3.7% (n= 18) positive both IgG and IgM antibodies . More than half of the workers were found having latent toxoplasmosis (53.0%) = previous exposure to infection.

8. 18 samples positive for both IgG and IgM antibodies tested for the IgG avidity test. • All samples were found to be > 40% (high avidity), suggesting past infection. • Majority of the workers in this study were provided with; • Suitable accommodation • Clean water system • Proper sewage toilets • Efficient waste disposal system. • More than 80% were fully covered for medical treatment • Provided with personal protective equipment (PPE) while at work Despite full amenities provided, high prevalence of latent Toxoplasmosis among migrant workers = acquired the infection from their home countries where the infections are prevalent (Rai et al., 1994; 1999; Gandahusada, 1991).

9. Table : Factors affecting seropositivity of T.gondii infection amongst migrant workers in Peninsular Malaysia using a non-parametric test (n=485).

10. Table : Multivariate logistic regression with full model for risk factors of T. gondii infection • Higher infection was found among workers above 45 years old (74.3%-76.9%) compared to those 44 and below years old (53.0%-59.2%). • Significant effect was also found between age group using multinomial logistic regression.

11. Infection increases with age: • in agreement with other previous studies (Tenter et al., 2000; Sobral et al., 2005; Ngui et al., 2011; Nissapatorn et al., 2004). • with an increase of age, the higher probability that an individual may associated with at least one of the mechanisms of transmission (Ngui et al., 2011; Apt et al., 1973; Amendoeira et al., 1999) • High infection prevalence amongst Nepalese: • Could be due to the habitual ingestion of minced raw meat or insufficiently cooked meat by some ethnic groups. • Dietary habit was the major contributing factor for high prevalence in Nepal as reported by Raiet al in 1994 and 1999 with positive rates of 57.9% and 65.3%, respectively (Rai et al., 1994; 1999).

12. Conclusion • Toxoplasmosis • One of the most important infectious diseases • Significant epidemiological and clinical impact on human (Nissapatorn et al., 2004). • Migrant workers in Malaysia need to be: • Educated on the various ways of acquiring toxoplasmosis • Provided with the proper knowledge to effectively prevent the transmission of this disease • This epidemiological data: • Provides evidence policymakers to include toxoplasmosis screening as mandatory for workers entering the country • A health surveillance program on toxoplasmosis is necessary

13. References • Hill DE, Chirukandoth S, Dubey JP. Biology and epidemiology of Toxoplasma gondii in man and animals. Anim Health Res Rev. 2005; 6: 41–61. • Montoya JG, Liesenfeld O. Toxoplasmosis. Lancet. 2004; 363: 1965–1976. • Feldman HA. Toxoplasmosis: An Overview. Bull N Y Acad Med. 1974; 50: 110-127. • Chan BTE, Amal RN, Noor Hayati MI. Toxoplasmosis among Indonesian Migrant Workers in Malaysia. MJMHS. 2009; 5(1): 31–37. • Rai SK, Shibata H, Sumi K, Kubota K, Hirai K, Matsuoka A, Kubo T, Tamura T, Basnet SR, Shrestha HG, Mahajan RC. Seroepidemiological study of Toxoplasmosis in two different geographical areas in Nepal. Southeast Asian J Trop Med Public Health. 1994; 25: 479-484.  • Rai SK, Matsumura T, Ono K, et al. High Toxoplasma seroprevalence associated with meat eating habits of locals in Nepal. Asia-Pacific J Public Health. 1999; 11: 89-93. • Gandahusada, S.. Study on the prevalence of toxoplasmosis in Indonesia: a review. Southeast Asian J Trop Med Public Health. 1991; 22: 93-98. • Tenter AM, Heckeroth AR, Weiss LM. Toxoplasma gondii: from animals to humans. Int J Parasitol. 2000; 30: 1217–1258. • Sobral CA, Amendoeira MR, Teva A, Patel BN, Klein CH. Seroprevalence of infection with Toxoplasma gondii in indigenous Brazilian populations. Am J Trop Med Hyg. 2005; 72: 37-41 . • Ngui R, Lim YAL, Amir NFH, Nissapatorn V, Mahmud R. Seroprevalence and Sources of Toxoplasmosis among Orang Asli (Indigenous) Communities in Peninsular Malaysia. Am J Trop Med Hyg. 2011; 85(4): 660–666. • Nissapatorn V.,Abdullah KA. Review on human toxoplasmosis in Malaysia: the past, present and prospective future. Southeast Asian J Trop Med Public Health. 2004; 35(1): 24-30.

14. Acknowledgements • Ministry of Health, Malaysia and relevant agencies/companies for assistance given for sample screening. • Medical staff and nurses from UMMC and HUKM for their technical assistance. • All volunteers participated in the study. • This study was supported by Fundamental Research Grant Scheme (FRGS) FP015-2014B from Ministry of Higher Education and PPP grant PG040-2014A from University of Malaya.

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