1. Introduction
1.1. Brief History of Anti-Malaria Operations in Thailand
The first recorded anti-malaria operation commenced in 1930 in northern Thailand, where efforts were limited to administering quinine and reporting annual malaria mortality [
1]. In 1932, the first “Shivering Fever Unit” was established in Chiang Mai province to clinically investigate and treat malaria patients with quinine free of cost, and to educate the population on how to avoid mosquito bites. In 1944, the centrally led Malaria Control Unit was upgraded to the Malaria Division within the Ministry of Public Health (MoPH) and was comprised of five zone offices in different regions of Thailand. Each zone had five malaria units and totaled 25 malaria units in 1945.
In 1949, malaria was the leading cause of mortality in Thailand with over 38,000 deaths, a rate of 2015 per 100,000 population [
1].
A 2-Year Malaria Control Demonstration Project (1949–1951) was supported by the World Health Organization (WHO) and UNICEF as a pilot project in Chiang Mai province using indoor residual spraying (IRS) with dichlorodiphenyltrichloroethane (DDT). The results were encouraging, leading the Thai government (in collaboration with the WHO and the United States government) to develop a country-wide Malaria Control Program (
MCP) from 1951–1957, covering 61 provinces within ten years [
2,
3]. The MCP adopted, evaluated, and revised various malaria control strategies from existing vector control methods, such as the countrywide spraying of DDT, along with anti-malaria drug distribution to at-risk populations concentrated in forested areas [
4]. In addition to these strategies, malaria clinics (MCs) established since the 1960s onwards have played a critical role for the MCP in providing early diagnosis and treatment for malaria. As a result of these combined strategies, the malaria death rate declined from 183.1 per 100,000 population in 1950, to 43.0 per 100,000 population in 1957, and further to 22.8 per 100,000 population in 1963 [
5].
In 1958, the Malaria Division began reorienting its MCP toward a Malaria Eradication Program (MEP; 1965–1970) in accordance with WHO guidance. The MEP was initiated in 1965. In 1966, there were 40 malaria laboratories performing malaria microscopy at the Malaria Division headquarters, regional offices, provincial malaria zone offices, and district malaria sector offices.
The malaria eradication effort ceased in 1971, and the government developed the MCP Plan (1971–1976) with a focus on remote and forested areas. This program aimed for control in areas of medium and high receptivity and eradication in areas of low receptivity, where malaria services were already partially integrated within the general health services. Receptivity being defined as presence/absence of Anopheles species.
Increasing malaria rates in the late 1970s ushered in an
MCP Reformation (1977–1996), which aimed to provide a comprehensive control program to all at-risk populations in Thailand. During the 1980s, the MCP faced several operational and financial constraints. The massive influx of refugees from Cambodia and the emergence and rapid spread of
Plasmodium falciparum (
P. falciparum) resistance to chloroquine and sulfadoxine/pyrimethamine resulted in malaria epidemics along the Thai–Cambodia border [
6]. Elsewhere in the country, malaria morbidity and mortality declined, with some fluctuations due to small-scale outbreaks. Malaria was highly prevalent in forested, mountainous areas along the borders (especially the western and southeastern borders) and the southern peninsula, but the central region (plains areas) was largely left malaria-free [
7].
In 1995, following the adoption of the Global Malaria Control Strategy, the MCP under the
Eighth Five-Year National Health Development Plan (1997–2001) aimed to reduce malaria morbidity and mortality with special attention on 30 border provinces. The MCP remained organizationally separate and vertical, although some activities, such as case detection, had been partially integrated into the general health services, especially in low malaria areas. Vector control activities and active and passive case finding at specialized MCs remained under the responsibility of the MCP structure [
3].
Reorganization of the MCP and integration into general health services commenced in 1996 (
Figure 1) in response to financial constraints, downsizing of government institutes, and the steady decline of malaria over the previous decade. The MCP merged with the Filariasis and Dengue Hemorrhagic Fever Control Programs at the regional and provincial levels.
In the new millennium, total malaria cases and deaths continued to decline. The Malaria Division became the National Vector Borne Disease Division in 2002; the integration of regional and provincial level vector borne disease (VBD) structures with other communicable disease programs occurred simultaneously. The malaria program remained semi-vertical within the Department of Communicable Disease Control (now the Department of Disease Control). Thailand saw a continuous decline in malaria burden from 64,957 reported cases in 2010 to 17,153 in 2016 and a morbidity rate of 0.38/1000 population, with much of the malaria transmission concentrated along international borders. This success paved the way for the Ministry of Public Health to develop a
Malaria Elimination Strategic Plan for Thailand 2017–2026 with the vision that Thailand will be malaria-free by 2024. To drive the Strategic Plan and monitor implementation progress, a different mechanism was required at the national level, i.e., the Committee on Sustainable Development Goals. Therefore, the Steering Committee on Malaria Elimination and the Administrative Committee on Malaria Elimination were established. At the provincial level, the Office of Public Health Inspectors, the Office of the Permanent Secretary, and the Department of Disease Control are responsible for transferring the policy, guidelines, and interventions through the Provincial Communicable Disease Committees, Communicable Disease Control Units (CDCU), the health facility units of both public and private sectors, and civil society organizations to implement the malaria elimination plan according to the local context of each area. [
8]. Thailand envisions the elimination of malaria by 2024 and aims to achieve this in more than 95% of districts by 2021, with all districts malaria-free by 2024. As Thailand has re-orientated its malaria control program to an elimination program, malaria stratification has been reclassified based on the district as the lowest administrative unit for elimination and updates on village-level malaria risk are issued annually. [
9]. Thailand has made rapid progress in targeting and reducing the number of active foci (villages) of transmission in the country from 1542 in 2015 to 415 in early 2018. The total number of confirmed malaria cases was reduced from 17,153 in 2016 to 13,974 in 2017. Remaining active foci are primarily located in three border areas: In the west with Burma; in the east with Cambodia, where high population mobility is associated with importation of malaria parasites and complicates surveillance; and in the south with Malaysia, where civil unrest inhibits service delivery [
10]. Overall trends in malaria incidence and mortality over 1965–2019 (until June) are summarized in
Figure 2.
1.2. House Visitor: The Role in 1960–1979 for Malaria Diagnosis–Treatment
Prior to the establishment of MCs, patients had to wait for house visitors (HVs) to visit households within their assigned areas at least once a month [
1]. Since 1965, HVs were contracted as permanent employees and the recruitment criteria were at least a secondary school education and one month of pre-service training. The training included knowledge of malaria, preparing blood films, pre-staining slides for microscopy, and health education. Usually, HVs would ask five screening questions about each member of the household, such as presence of fever and history of visiting malaria endemic areas. A blood film was prepared for those who replied “yes” to at least one question. For symptomatic individuals, “presumptive treatment” consisting of chloroquine and pyrimethamine (for adults) was given to control the spread of malaria infection and reduce mortality. The HV would return to the Malaria Zone offices in the last week of the month to send the blood slides to the laboratory, submit blood record forms, and prepare materials for the next round. The blood slides were examined at the Malaria Zone Office; if found to be positive for malaria, the HVs would return the following month to give “radical treatment”. The average turnaround time from slide collection to radical treatment was around one month, but sometimes longer in laboratories with a high volume of slides [
11]. Besides the routine HV activities, squad chiefs were appointed as the senior HVs in a given area to coordinate and supervise the HVs. HV squad chiefs intermittently collected blood films and sent these to the provincial-level Malaria Zone Office laboratory. Similarly, the chiefs of district-level Malaria Sector Offices were also tasked to investigate and treat cases. MCs were initially staffed by HVs, who were formally re-designated as “Malaria Clinic Workers” in 1979 and stationed at Malaria Sector Offices [
12].
1.3. Human Resources in the MC
There are three main categories of government-employed staff in Thailand. First, Civil servants, such as doctors, nurses, technical staff, administration staff, heads of the vector borne disease control center (VBDC), vector borne disease control unit (VBDU), etc., are eligible for training opportunities and promotion to higher positions. Second, there are permanent employees, like HVs, senior HVs, chief of malaria spray teams, drivers, laboratory staff at the VBDC, data entry staff, entomology field workers, etc. Job descriptions are generally fixed with very little change over the years. Training opportunities have been limited, and promotion requires passing relevant examinations. However, this category offers better job security than temporary employees, who are recruited for specific periods and tasks like project staff, spray team members, etc.
Over the years, HVs, senior HVs, and some chiefs of malaria spray teams who fulfilled the criteria were employed as MC workers and remained as “permanent employees”. Although they remained in the same position (of HV) with the same salary scales, many HVs opted to work as MC workers and received the local community’s support and respect [
13] personal records.
Prior to the 1980s, when more civil servant positions were created, MC workers had promotion opportunities and could pass the required examinations easily, having more knowledge of malaria and public health than most other applicants. This saw many of the House Visitors and MC workers become heads of the VBDC and VBDU. However, from 1980 onward, this practice stopped and VBDU staff were recruited and trained as other staff of the Provincial Health Office (PHO) (personal records).
In the 1990s, the government imposed a new rule on downsizing government staff recruitment. Recruitment for vacant permanent employee positions was stopped. However, as MC workers were still relatively young, this had little effect till the 2000s and onward, when many MCs were closed largely due to MC worker retirement and attrition. In addition, unlike civil servant positions, MC workers could not be reassigned to a new district or province where they were needed most, as they were not entitled to house rent and other subsidies (personal interviews and records).
2. Materials and Methods
The objective of this study was twofold. Firstly, to document the role of MCs and analyze quantitatively the impact in providing early diagnosis and effective treatment of malaria; and secondly, to assess the relevance of MCs in the context of malaria elimination in Thailand. We performed a literature and document review regarding MCP and MCs from published articles, unpublished reports and data, annual reports (ARs) of the Malaria Division, Department of Communicable Disease Control, Ministry of Public Health, Thailand from 1975 to 2018, and personal records of the Division of Vector Borne Diseases (DVBD) senior staff members. Aside from journal published articles, all records were in Thai and required the translation of S.H on relevant sections. We discussed the future factors most affecting the work of the MCP and MCs with senior staff members of the DVBD. To protect the confidentiality of the interviewers, their opinions were given without any links to their names or organizations. Personal records were obtained from two of the senior authors. All information was reviewed and analyzed. Since this article did not involve personal identifiable data and used only secondary data, an information sheet and consent forms were exempted.
Data for malaria incidence and mortality, number of MCs, percentages of slides examined, and positive cases detected at MCs were obtained from the DVBD, Department of Disease Control, Ministry of Public Health, Thailand. Malaria incidence and mortality were each plotted against the number of MCs from 1965 to June 2019. Number of slides examined and number of positive cases detected at MCs were each analyzed in three-year increments. The years 1965–1974 were omitted because of missing data from MCs in some years. Tables 1 and 4–7 were created using the Self Analysis tool on the Thailand GMS Malaria website:
http://thailand.gmsmalaria.org/. Cases were filtered by year, foci, case classification, nationality, and province. To find cases from MCs specifically, cases were further filtered by health facility. All
p-values were calculated via univariate chi-squared tests in the R statistical program (version 3.5.2; Foundation for Statistical Computing, Vienna, Austria, 2013).
4. Discussion
The evolution, roles, and contribution of MCs since their establishment until 2015 is summarized in
Figure 11.
The set-up of the MC in Thailand is unique. There are a few parallels with other countries in the region of similar extensions like MC that arise from the malaria program vertical system. Although the authors did not conduct an in-depth literature review of successful malaria programs where MC-like structures have been employed, the use of MCs in three highly successful malaria elimination programs in the region was studied. These MC-like initiatives were part of the formal ministry structure, thus were government funded as opposed to project or donor funded; therefore, they were more sustainable over time. The use of subsector malaria offices in remote parts of Sabah, Malaysia [
18], mobile malaria clinics in Sri Lanka [
19,
20] and malaria control consultation and service posts (MCCSPs) along the border areas of Yunnan province, P.R. China [
21], showed that despite specific differences and contextual circumstances in their initial development, there were commonalities in all three countries.
Firstly, the primary objective was to hasten and improve access to diagnosis and treatment for malaria patients with a minimum delay after the onset of the illness. Although disaggregation of data by facility and robust analysis was not possible in the initial years of operation, the MC service in Thailand significantly improved patient turn-around time to 30–40 min between diagnosis and treatment as compared to a month. Patient satisfaction with this service proved to be an important impetus that not just established the popularity of MCs, but also led the program managers to further expand its utility. By being responsive to the changing epidemiology and the need to reach different at-risk populations, including outbreaks, the Thai program began diversifying MC service delivery channels from “fixed MCs” within existing facilities and stand-alone MCs to MMCs and FSMCs. Along the geographical expansion, the contribution of MCs to blood slides tested increased 10-fold (39.8% of all malaria slides from 1988 to 1990) compared to the previous decade, with a record 54.8% positivity rate of those tested at MCs. Although the proportion of positive cases detected at MCs initially declined after 1990, it has since remained relatively stable around 30–35%.
Secondly, there was government investment in not just the initial infrastructure (building, vehicle, equipment, etc.), but also the employment, training, and on-going supervision of microscopists, field officers, laborers and occasionally a Public Health Inspector at MCs as in Sri Lanka. The Thai program proved that even though domestic financial constraints in the early 2000s necessitated the closing of a few MCs, it was still possible to focus on current challenges: The increasing number of unregistered migrants diagnosed with malaria and the emergence of artemisinin and multi-drug resistance. MCs, especially in areas bordering Myanmar and Cambodia, diversified by providing free long-lasting insecticidal nets (LLINs) for unregistered migrants diagnosed with malaria and commencing radical treatment for Pf with supervised treatment until day 3, and a follow-up on days 7, 28, and 42. Further investments from donor agencies allowed the program to employ additional human resources (microscopist, additional microscopes, and IEC/BCC staff and workers) to follow up with patients, as well as to conduct foci investigations and mass blood surveys.
Thirdly, in areas where malaria burden declined to very low levels as with elimination settings, MCs focused more on mobile or outreach activities to screen the populations of districts with high vulnerability and/or receptivity for malaria and to maximize case detection through RACD or PACD. This allowed for a higher yield in case finding and, through prompt and effective treatment, reduced the parasite reservoir and the possibility of further transmission. The Thai program, in its nascent elimination phase, should learn where and how MCs can be best utilized in ACD activities from the three MC-like examples. In leading up to the WHO certification of elimination, these approaches will strengthen the evidence that there is no indigenous transmission in areas that were screened actively and periodically through the outreach of the MCs. A proposed framework for this is outlined in
Figure 12. This figure looks at cases in the four different foci areas, specifically the proportion of these cases that were seen by MCs and the percentage of cases within MCs that were indigenous or imported. Based on the trends in these numbers, we recommend an approach to malaria elimination tailored to each foci area.
The authors acknowledge certain limitations in this research. The authors relied largely on secondary data from both published articles and unpublished reports and data, annual reports (ARs) obtained from the DVBD and Department of Communicable Disease Control, Ministry of Public Health, Thailand from 1975 to 2005. The years 1965–1974 were omitted in this research because of missing data on MCs in some years. Personal records of the senior staff members that were interviewed, although extremely valuable, could not be validated. Due to limited resources for this research, the authors could not conduct interviews with either retired or current MC staff. Although we analyzed and presented the main outcomes of the 1-3-7 on trends of transmission, such as case profile and foci, the actual performance of the MCs against the national program indicators for monitoring the performance of 1-3-7 was not assessed. Case notification, investigation, and response rates specifically disaggregated by MCs could not be performed due to technical issues with the web-based surveillance platform.
Another important area for further research would be to analyze in detail the human resource situation, especially at the district and lower levels (elimination implementation unit). A detailed profiling of staff (staffing numbers, anticipated retirement age, capacity gaps, workload required to meet elimination targets, etc.) within the vertical malaria network of VBDU and MCs will be critical. This would require the use of qualitative tools to appraise and the exploration of future replacement strategies at the district level critical about the roles and resources of the CDCU, district health office (DHO) local administration organizations, health promotion hospitals, private health facilities, and civil society organizations. This analysis should be performed to be in line with the positioning of malaria elimination as a part of the general health services and with the 20-year Thailand National Health Strategic Framework (2017–2036).
5. Conclusions
Malaria clinics have served communities in Thailand for almost six decades and are still playing a critical role in providing early diagnosis and effective treatment of malaria. Between 2017 and June 2019, during the malaria elimination phase, MCs continued to test an average of 67% of all persons tested for malaria and confirmed 38% of all positive cases detected in the country. However, both the testing and positive rates are on a gradual decline as the overall burden of malaria declines annually, which may reflect decreasing transmission intensity. Since 2000, several MCs in areas with zero reported malaria cases and absence of mosquito vectors have been closed. Most experienced field MC staff have retired. Although the number of MCs in the last three years has been stable (n = 240), the attrition of MC staff, especially microscopists, poses a real challenge to the longevity of MCs in the absence of a human resource plan to support the elimination phase.
As Thailand’s malaria program becomes increasingly decentralized and integrated into general health services, it will be important to maintain the technical and programmatic capacity to manage core malaria services, including analysis and decision-making, at the sub-national level. Although the CDCUs are initially expected to take over functions of the MCs with regard to the case and foci management in areas where malaria transmission is very low (B1 areas), it will be necessary to identify and support capacity gaps and needs during this period of transition from a strictly vertical program to an integrated and decentralized program, while ensuring that the DVBD maintains its necessary technical and advisory role for malaria control and elimination within the MoPH.