Perception and incidence of Buruli ulcer in Ogun State, South West Nigeria: intensive epidemiological survey and public health intervention recommended

Introduction Buruli ulcer (BU) is a highly ranked neglected tropical disease (NTD) of global health importance with increasing incidence in sub-Saharan Africa yet there is paucity of information on the epidemiology of BU in Nigeria. Incidentally, highly BU endemic Benin Republic shares proximity with Nigeria. This study was carried out to establish presence of BU and ascertain the level of BU perception among rural populace in Ogun State, south-west Nigeria. Methods Secondary data (2009-2012) on incidence of BU was collected from a reference hospital. A cross-sectional survey using structured questionnaire administered to rural people and healthcare practitioners was conducted in three purposively chosen Local Government Areas (LGAs) in Ogun State based on unpublished reports of BU presence. Results Data collected revealed 27 hospital confirmed BU cases between 2009-2012 across four LGAs (Obafemi Owode, Abeokuta North, Yewa North and Yewa South) while 14%(21/150) chronic ulcers (suspected to be BU) were discovered during the cross-sectional survey carried out in Odeda, Yewa South and North LGAs. Healthcare practitioners 63.6% (42/66) and 54.7% (82/150) rural people demonstrated poor level of BU perception respectively. Conclusion This study provides evidence that BU exists in Ogun State and evaluates the poor perception that the affected rural populace has on the disease. This pilot study presents baseline information on BU in a rural setting in Ogun State South-west Nigeria hence the vital need for prompt public health involvement and further research on the epidemiology of BU.


Introduction
Buruli ulcer (BU) is an emerging tropical disease predominant in West Africa, affecting mostly rural populace who most times are quite ignorant of the disease. The BU is a very devastating disease of humans and animals caused by an environmental nontuberculous mycobacterium (NTM), Mycobacterium ulcerans [1][2][3][4][5].
Children under the age of fifteen years have been found to be commonly affected by this highly rated neglected tropical disease (NTD) inflicting huge impact inform of deformities, functional limitations and social stigma on them when assessed by disabilityadjusted life years, DALYs [6][7][8][9]. Increased morbidity due to extensive necrosis of the skin, subcutaneous tissues, bones involvement and varying degrees of contracture on BU patients is very common and compounded with inadequate or no access to health care services in rural settings, all contributing to the lowest possible standard of living among affected people [2,[10][11][12][13]. The global health concern for BU as revealed by WHO classification of NTD shows that BU is a top ranking emerging NTD [14]. Although BU is noted as the third most common mycobacteriosis, some communities in the sub-Saharan Africa are recording incidence surpassing Tuberculosis and Leprosy [7,10,[15][16][17]. The causative agent M. ulcerans has affinity for aquatic areas; rivers, streams, farmlands, irrigated areas, where majority of the rural poor conduct several livelihood activities ranging from farming, fishing to fetching water for domestic purposes [1,10,[18][19][20][21][22][23][24].
Despite increased geographical spread of Buruli ulcer in sub-Saharan Africa especially in West Africa, there is dearth of information on epidemiology of the disease in Nigeria when compared with some of West African countries: Ghana, Benin Republic, Togo, and Cameroon [7,10,[25][26][27]. Previous reports on BU in Nigeria have always been focused on clinical cases recorded either by hospital presentation or as a result of active case searches [16,[28][29][30][31]. The epidemiology of BU is very important due to its yet to be unraveled mode of transmission which also hampers efforts to prevent and control the disease [10, 20,21,32,33]. Consequently, information on the perception of BU disease among the most predisposed rural populace is very vital in achieving the meaningful goals of finding out the prevalence of BU which is uncertain in most endemic countries, encouraging early reporting by affected people and ensuring prompt treatment thereby preventing the extensive devastating effects of BU [20,34,35]

Study location
This study was undertaken in Ogun state, one of the six states in

Data analysis
Data were analyzed using SPSS ® (Statistical Package for Social Sciences) version 20. Socio-demographic variables were summarized using descriptive statistics. The Sign-test for nonparametric data was used to analyze the socio demographic predictors of BU perception among the rural people and healthcare practitioners. Significance was set at p ≤ 0.05.

Buruli ulcer presence in Ogun State
The hospital record of Hansen's disease center Iberekodo located in  Figure 1). Yewa south recorded the highest number (9), followed by Odeda (7) and Yewa north (5). The duration of the ulcers ranged from 1-35years and majority were located on the lower extremity but only one case was found at the back.

The outcome of cross-sectional survey
A total of one hundred and fifty (150) Table 2.

Discussion
Difficulty in unraveling the mode of transmission of M. ulcerans the causative agent of Buruli ulcer creates a huge obstacle in proffering actual preventive and control strategies for this debilitating disease ravaging impoverished population in sub-Saharan Africa [37,38]. To achieve these phenomenal feat, in-depth epidemiological studies on BU is of paramount importance most especially in the endemic West African region [7,21,33]. The population at risk has enormous part to play in providing relevant information on the disease which will enable researchers to be well equipped with essential information Several studies involving active BU case search have been successful in Nigeria and in some African countries towards epidemiology and molecular studies of BU disease [16,24,29,30].
The focal distribution of BU was also highlighted in this study which is in line with findings from previous reports from some West African countries [38,40]. The cross-sectional survey involving questionnaire administration yielded results from the study location with the highest number of BU patients emanating from Yewa South LGA hence tallying with the report from the hospital records. This may not be unconnected with the close proximity that this LGA shares with highly endemic Benin Republic. Reports have it that many BU patients from Nigeria access medical help from neighbouring countries [40]. Odeda LGA had no previous BU report but are susceptible on account of the predisposing risk factor of culpable aquatic environments situated within the communities.
There is there possibility of Odeda becoming new BU foci. Majority of the ulcers were located on the lower extremity in accordance with previous reports [16,32] attributing this to probably the ease of contact with risk factors.

People living in Yewa South and Yewa North
LGAs were more willing to participate in the survey perhaps because there were BU patients within these localities. However in the healthcare practitioner category, more well-disposed respondents were encountered in Odeda LGA. The closeness of this LGA to Ibadan; a peri-urban city must have been the reason associated to this, as healthcare service delivery seems more accessible. This study equally highlighted increased number of CHCW revealing their impact on rural health care delivery thereby affirming previous studies carried out in Republic of Benin and in sub-Saharan Africa [41][42][43]. There was generalised evidence of poor perception across the study area, pointing to the high level of ignorance on BU among the rural populace. Majority attributed occurrence of BU to witchcraft, spiritual attack, ancestral curse and affliction by "ofa" hence the believe that only appeasing the gods, certain sacrifices, traditional healing and deliverances can remedy BU. The availability of free BU treatment opportunity was only known by few healthcare practitioners and some BU patients who had received prior treatment. Women were more knowledgeable, most likely because they bear most of the burden suffered by BU patients directly [43][44][45]. Although CHCW contributed immensely to the care of BU patients they still had poor perception on BU most likely because of their low level of education. From this study, education of both rural populace and healthcare providers cannot be over emphasized.

Conclusion
Globally Buruli ulcer disease has assumed a great health concern because of the severe pain, disfigurement and harsh economic burden on affected people. Efforts are on to discover the exact mode of transmission, extent of spread through geographical mapping, rapid diagnostic techniques which will easily be accessible in the rural areas and for more national sustainable surveillance.
Population studies are very important in understanding peculiar diseases inherent in a population. Information on such diseases from the affected people offers very important direction mostly to researchers. Ascertaining the perception of people from this study on BU has provided a vital overview on the knowledge of BU exhibited by these communities; which were fundamentally wrong.
Majority of the people affected did not believe that BU is treatable; many believed that witchcraft was the cause and many more did not know that treatment was free. This study has thrown more light on these grey areas and will subsequently spur many to access medical help early to forestall extensive consequences. It is therefore recommended that the Government of Ogun state should increase efforts to strengthen the public health department to undertake intensive and extensive epidemiological studies on BU in all LGAs of the state as this will help in establishing the prevalence of BU in the state. The federal ministry of health equally should have an extended plan of conducting national survey on BU across Nigeria to ascertain the status of Buruli ulcer in Nigeria.
What is known about this topic  Buruli ulcer is a neglected tropical disease highly endemic in West Africa;  Close proximity to aquatic environment is a risk factor.
What this study adds  This study provides probable level of BU endemicity and the level of BU perception by the population (rural populace) highly at risk in Ogun state;  It also promotes essential aspect of increasing awareness on BU especially among the population at risk.

Competing interests
Authors declare no competing interests.  Tables and figure   Table 1: Socio-demographic predictors of Buruli ulcer perception among rural people