Morbidity and mortality due to malaria in Est Mono district, Togo, from 2005 to 2010: a times series analysis

Malaria remains a major public health concern. According to the World Malaria Report 2010, the global prevalence of the disease was estimated at 225 million cases and 781,000 deaths in 2009 [1]. About 80% of these cases occur in sub-Saharan Africa, with rural areas that have poor access to health services being most affected [2, 3]. In Togo, malaria is a priority disease because of the high morbidity and mortality associated with it. The disease accounted for 39% of out-patient consultations, 21% of hospital admissions and 4.9% of case fatalities in 2007 [4].

Malaria control strategies primarily comprise prevention through vector control, such as indoor residual spraying (IRS) or the use of personal preventive methods such as bed nets and mosquito repellents followed by chemoprophylaxis. Control also takes the form of effective case management and medication. The implementation of these strategies has been supported by donor funding and the commitment of governments and partners from many countries [5]. In many developing countries there is variable success in vector control using insecticide-treated bed nets (ITNs) and IRS with dichlorodiphenyltrichloroethane (DDT) or other agents [6, 7].

Since 2004, the Togolese government has adopted a regional strategy of malaria control through the use of ITNs, the use of artemisinin-based combination therapy (ACT) as well as community involvement [4]. Malaria control strategies in Est Mono district include promotion of the use of ITNs in the community, which is one of the main technical approaches of the Roll Back Malaria campaign (RBM), implemented in late 2004 in Togo. In 2007, the country started the implementation of artemether–lumefantrine as first-line treatment for uncomplicated malaria in all public health facilities and by community health workers (CHWs) because rapid diagnostic tests (RDTs) to confirm malaria could be carried out even in health facilities that did not have the laboratory capacity. CHWs were trained to promote health, treat uncomplicated malaria cases within their communities and report data to their respective health care centres. These strategies aimed at increasing the accessibility of health care to isolated populations and those populations living beyond five kilometres of health facilities and to reduce morbidity and mortality due to malaria by 50% in 2012 from 2005 levels [4].

After five years, the impact of the implementation of the new malaria control strategies on the malaria burden in Est Mono district remained unknown. The objective of this study was to assess the trends of malaria prevalence and specific mortality due to malaria in Est Mono district from 2005 to 2010.

The data presented here demonstrate that reported malaria cases remain high in Togo. Indeed this study found an overall increase of malaria cases in Est Mono district of 159% in 2010 from the 2005 level. The proportion of confirmed malaria cases also increased from 17.7% in 2005 to 85.9% in 2010. The government targeted a reduction in morbidity and mortality due to malaria by 50% in 2012 [4]. The national health information reports show an increase of malaria incidence from 80 per 1,000 in 2005 to 160 per 1,000 population in 2010 [13]. Several explanations exist for these observations. With the implementation of the new scale-up policy, there has been increased access to affordable interventions for malaria care even to populations that live more than five kilometres from a health centre. Indeed, the cost of ACT in Togo is relatively low (USD2) for a treatment course compared to the average cost of a case treatment (USD10) before 2007 in the public health centres of the district [8]. This is supported by the increase of the total number of health care visit in Est Mono district during the study period. In Kenya, it was shown that the rate of health care use increased when free high-quality care was offered [14].

The implementation of the new policy of malaria control in Togo took into account the enhancement of health care [4]. These findings suggest that several factors had impacted on the number of malaria cases reported throughout the six years – including the training of health personnel in malaria case management; the introduction of a new treatment at lower cost; the involvement of the community through the CHWs; improvement in the monitoring and reporting system and the use of new RDTs that are simple and quick to perform and show high sensitivity. The findings are consistent with those of Nyarango et al. from an Eritrean study, where it was reported that the incidence of malaria was influenced by many factors. These factors included the access to diagnosis and treatment, risk perceptions of the net users, the training of health workers, as well as the involvement of community health agents, who increased the proportion of malaria cases treated in the community from 50% to 78% [6].

A study conducted in Uganda in five selected hospitals over a longer time period (1999 to 2009) reported a significant increase in paediatric malaria admission [15]. The reasons given were the abolition of user fees in the hospitals, low intervention coverage and the high malaria transmission. In Malawi, there was no decline in annual malaria prevalence among children from 2001 to 2010 because of the disparity in treated bed coverage and the low coverage of IRS [16].

In contrast, a decline in malaria incidence has been reported in many countries [6, 9, 14, 17‐21] but in most of these countries the interventions implemented included IRS and the involvement of CHWs. Similarly, in a much larger study in South Africa, where IRS was implemented and use of ACT was introduced sequentially, a reduction in the incidence of malaria was observed after implementing the use of ACT [22]. In Togo, IRS is an intervention included in the strategic plan [13] but it has not been implemented yet. ITNs remain widely used for malaria control in Togo. Nyarango et al. [6] and Sharp et al. [23] state that ITNs remain the intervention of choice for prevention of morbidity and mortality from malaria in areas of high transmission. But the preventive effect of ITNs depends on their insecticidal properties and physical integrity [24]. In a recent study conducted in Ethiopia the combination of ITNs and IRS was found to be more effective as a control measure [25].

The results of the Togo study suggest that strengthening of the malaria reporting system by the control programme could have increased the number of reported malaria cases in Est Mono. Malaria cases could have been under-reported before the introduction of the new malaria control policy, which included the enhancement of case reporting.

In this study area, there was a decrease in mortality rate from 7.2 per 10,000 in 2005 to 3.6 per 10,000 in 2010 and an increase of laboratory-confirmed cases. These findings are consistent with national data [13]. The steady decline in mortality due to malaria observed in this study has met the national target of reducing mortality by 50% by 2012. The early clinical diagnosis with laboratory confirmation and appropriate treatment using ACT as recommended by the national guidelines are the main factors that could have contributed to the decline in mortality due to malaria in Est Mono district. It is well known that the early clinical diagnosis and laboratory confirmation are essential aspects of effective care and effective case management of malaria [6].

A study conducted in the province of KwaZulu-Natal in South Africa showed that the use of ACT decreased by 97% mortality due to malaria [22]. Similarly, in Zanzibar the decline by 52% in mortality due to malaria among children under five years old was observed after deployment of ACT [21]. The availability of ACT in Togo and personnel training in malaria case management should be reinforced.

The rainfall was correlated with the prevalence of malaria in the Togo study. The findings are consistent with findings elsewhere [6, 9, 10, 26] and confirm the role played by climatic and seasonal factors in the malaria burden. However, the pattern of rainfall did not change markedly over the six years of the study. The time series analysis shows also that the increase in reported malaria cases could be attributed to the role played by the CHWs trained in malaria case management.

This study shows an increase of reported malaria cases and a reduction in mortality due to malaria in Est Mono district with the introduction of ITNs, ACT and the involvement of CHWs. Multicentre data analysis over longer periods should be carried out in West African countries where the transmission of malaria is still high to find out the impact of malaria control strategies on the burden of the disease. The introduction of IRS and other integrated vector control management strategies in Togo needs to be considered for reducing malaria transmission in order to meet the Abuja Declaration goals, which are only three years left from deadline.