Among migrant workers in Trat, Chantaburi, and Sa Kaeo provinces on the Thailand-Cambodia border, substantial differences exist between migrants who have been in Thailand for less than six months and longer-term migrants, and between migrants from Cambodia and those from Myanmar. These differences must be taken into consideration when designing malaria control strategies.
Cambodian migrants were more likely to be short-term workers, male, under 25 years of age, with little formal education, very little knowledge of spoken or written Thai, and working in the agricultural sector. Longer-term workers from Cambodia had more access to education and a majority spoke Thai, though few read it, and there was a broader range of occupations. Migrant agricultural workers typically work and sleep on one farm, dependent on the farm owner for access to services, and thus may have limited access to health services and messaging. Many would likely not benefit from radio or TV messages in Thai heard at their residences or workplaces. Migrants from Myanmar had a longer duration of residence in Thailand, and while their level of formal education was similar to Cambodian M2, the majority spoke Thai, though few read it. While most worked in rubber tapping, about one-third owned their own home and were more integrated within the community, with greater access to health services and messaging.
Consequently, knowledge of malaria differed among migrant groups. While the majority of long-term migrants are knowledgeable about malaria transmission, prevention, and treatment, a consistent one-third of short-term migrants from Cambodia reported little to no knowledge of these factors, yet had the highest proportion of persons reported treated for malaria in the previous 3 months. While most cited bed nets as a preventive measure, and the overwhelming majority of migrant workers from Cambodia and Myanmar own and sleep under bed nets, the proportion that knew to get anti-malarial medicines from a health care worker was comparatively low. Long-term migrants were more likely to have received health messages than short-term migrants, and those from Myanmar more likely than Cambodians. Migrants from Myanmar were much more likely to receive messages from a health care worker than Cambodian migrants, perhaps due to the higher use of public health facilities.
These results suggest the need for more targeted and effective health messaging in migrant communities, especially in among short-term migrants from Cambodia. Given the low level of Thai literacy, oral media, such as health care workers, television, and radio were the most effective mediums used. Presenting oral material in native languages, such as Khmer, may be the most effective strategy to reach short-term migrants. While brochures reached very few, levels of Khmer literacy among Cambodians and Burmese literacy among those from Myanmar indicate that using printed material in the native language may be effective. Well-developed and evidence-based Information, Education and Communication (IEC) and Behaviour Change Communication (BCC) materials are needed to increase knowledge in the community of symptoms, prevention and control measures, sources of treatment and care and the risks associated with delays in treatment [9
]. Strategies and materials need to be based on the needs, characteristics, and culture of the migrant workers in the areas [17
Clearly, access to health insurance influences health care-seeking patterns; most migrant workers from Myanmar have health insurance in Thailand, and not surprisingly are more likely to use government health facilities than Cambodians, a majority of whom do not have health insurance and return to Cambodia to seek care. Short-term migrants are even more likely than long-term migrants to return to Cambodia for health care, and have a high rate of self-treating or not seeking treatment.
The most important determinants of treatment-seeking behaviour for both nationalities were proximity and cost. Access is a concept involving awareness of people's need for medical care service, availability of services and acceptability of the service and affordability to the service [24
]. Regulations and policy for malaria control and prevention were different and continuously evolving between Thailand and Cambodia; for example the issues of case management and free access to health care services [25
]. Previous studies in the region have reported factors associated with health care services access and utilization. In a study on health-seeking behaviours among Myanmar migrant workers in southern Thailand [26
], buying drugs from a drug store was the most common health-seeking behaviour when the health problem was perceived to be minor, but care was sought at health centers for health problems perceived to be major. The choice among the available options was determined by the availability of health facilities, cost fees, satisfaction with services, accessibility, knowing where and how to obtain health services, and belief in traditional medicine.
Community-based interventions and services through a network of village health workers (VHWs) and community volunteers to strengthen malaria prevention and control measures may be particularly useful for the Cambodian migrants that have little access to health services [27
]. In Thailand, IOM has piloted several field projects to develop the Migrant Health Programme Model [29
]. The model further promotes migrant community volunteers who are in a position to culturally interact with migrants, promote good health practices and collaborate with Thai health workers to increase access to and use of basic health services, including malaria services, by migrants. Migrant health teams, which are part of the model, are also set up at district and provincial levels to ensure that challenges are discussed, addressed and monitored at policy decision levels.
It will be essential for the BVBD and the Cambodian National Malaria Programme (CNM) to work together on effective cross-border strategies taking into account the migrant's level of education, language, usual point of access of health messaging, and mobility. It is also essential that these strategies include employers as for many migrants, work is their only point of access to health messaging and services. This will necessitate the development of a strategy with the Ministry of Labour to approach employers who are using undocumented workers in a non-threatening way. While core universal approaches to prevention and control measures for all migrants along the border should be utilized, different approaches and strategies should also be planned for each respective group in order to reach effectiveness in major goals for disease containment or elimination. Changes in population distribution and migration trends should be taken into consideration. The IEC/BCC development and malaria control efforts should identify how to refine, simplify and scale up replicable interventions that will add value and impact to a regional concept rather than just country-specific plans, and should not ignore vulnerable and hard-to-reach ethnic minority populations.
In addition to the activities outlined above, medical insurance and assistance programme options are under consideration in Thailand to provide affordable health care services to all migrants [26
]. In addition, advocacy combining social networking and mobilization, interpersonal communication and negotiation, as well as the use of media for generating public pressure might be effective tools for health care professionals to make sustainable social change [32