Environmental, economic and socio-cultural risk factors of recurrent seasonal epidemics of cerebrospinal meningitis in Kebbi state, northwestern Nigeria: a qualitative approach

Nigeria is one of the countries that lie along the traditional African meningitis belt which spans from Senegal in the western part of the African continent to Ethiopia in the eastern part [1–3] Characteristically, cerebrospinal meningitis (CSM) epidemics start around February when the prevailing weather is hot and dry and tails off with the onset of rainfall in May or June [1–3].

Until recently, Neisseria meningitidis type A was the major cause of seasonal CSM epidemic within African meningitis belt [4–7]. However, other serotypes have been implicated in recent outbreaks in different parts of the belt, such as C, W135 and X [4, 6–8]. There are other bacterial pathogenic agents that are capable of causing an outbreak, however, on a smaller scale [4, 5].

Northern Nigeria has experienced recurrent seasonal CSM epidemics for several years, despite efforts being made by the government and development partners [5, 7, 9]. The recurrent CSM epidemics are of public health importance due to relatively high morbidity and case fatality rate, the huge population at risk and the over-stretching of the weak health services [7, 9, 10]. Most recently, between January and April, 2017, outbreak of type C meningitis was reported in northern states of Zamfara, Sokoto, Kebbi, Katsina, Niger and Yobe with it attendant high death toll.

Some interventions have been conducted in Northern Nigeria, including, a mass vaccination campaign against Neisseria meningitidis type A, reactive vaccinations against type C, episodic health education, and more recently, strengthening of laboratory surveillance for CSM [5, 7, 9]. Reactive vaccination is a vaccination response rapidly conducted to contain the spread of an epidemic within a defined geographic area.

Despite these efforts, the epidemic belt seems to have expanded in Nigeria from 26 to 29 states, and within states, for example, in Kebbi State, between 2014 and 2015, the number of affected Local Government Areas (LGAs) has increased from 10 to 16 [7]. Similarly, Kebbi State remains the epicentre of seasonal epidemics of meningitis in Northwestern Nigeria, given the magnitude and recurrent nature of the outbreaks [7].

Literature suggests some factors that underlie the spread of seasonal epidemic meningitis, though not fully elucidated [3]. For example, elements like climatic conditions- temperature, humidity, dustiness; previous history of meningitis; poor housing condition and household crowding; income and poverty level have been associated with seasonal epidemic meningitis. Most of these studies were not indigenous, and also, no recent published study has been done in Northern Nigeria to investigate and better understand the factors that may explain the recurrent nature of the seasonal scourge. Moreover, there is no study to the best of our knowledge that investigated these factors using a qualitative approach.

In the light of the above, we conducted a study to ascertain potential socio-cultural, economic and environmental factors that could enhance seasonal transmission of CSM in Kebbi State. The identified potential factors could be used to modify or reduce community vulnerabilities to CSM infection and transmission and could be complementary to the role of mass vaccination. Providing a more effective and multi-pronged intervention becomes imperative given the pathogenic shift observed post- mass vaccination campaign in 2013, a limited global stockpile of CSM vaccines for outbreak response and funding issues.

Our study revealed the presence of favourable environmental, socio-cultural and economic factors linked to the spread of recurrent meningitis in Kebbi State.

Our findings showed that the affected communities were aware and appreciated the existence of a temporal relationship between onset of the seasonal epidemic and the prevailing hot and dusty weather while the falling of the rains signified the end of the epidemic. A similar finding was reported in 2014 by Codjoe and colleagues, who conducted an FGD to elicit the perception of communities about the relationship between climatic conditions and the CSM epidemics [12] . They reported that “the majority of participants rightly linked CSM infections to dry, very hot and dusty conditions experienced during the dry season” [12]. Other studies have used different techniques to provide the relationship between CSM infection and certain favourable climatic conditions, such as dusty and windy atmosphere, long period of dry and hot weather, low rainfall and low humidity [13–15] .

The literature suggests that deforestation activities expose affected areas to the ventilation of aerosols and dust, thus increasing the risk of transmitting meningococcal infection [13, 16]. The impact of poor urban planning and building control reflects as the houses in the studied communities had poor ventilation (mainly small window size, person per room varies from 4 to 10) and congested structures. Our finding is in tandem with evidence from existing literature [12, 17] implicating the poorly ventilated rooms and congestion. However, Feraro and colleagues did not find an association between household crowding and self-reported respiratory symptoms in a study conducted in seven countries within the African meningitis belt [18]. This disparity in findings might be explained by the “unrestrictive definition” (those who eat from the same pot) of household used in the study [18].

The information from participants clearly demonstrated the role of poor economic condition as a risk factor for recurrent epidemic meningitis in the study areas (Aliero and Jega LGAs). The role of economic factors has been documented in the literature regarding resilience or individual and community vulnerabilities to infectious disease transmission [19–21]. Specifically, some studies have linked poor household income, unemployment, use of firewood for cooking and neighbourhood social deprivation role in the perpetuation of respiratory diseases and other communicable diseases epidemic [19–21]. There exists widespread poverty at household levels, and many of the neighbourhoods are socially-deprived with poor sanitation, poor nutrition, low level of education and massive unemployment as well as a disproportionately high number of low-income earners. We also observed that the major source of cooking fuel was firewood and could have a role in the spread of airborne infections or respiratory tract infections such as CSM. Some of the component of the fumes may stimulate inflammation, coupled with the dry and hot weather, and then facilitate the invasion of pathogenic meningococcal meningitis. All the economic indices at household and neighbourhood levels were poor. Hence, the communities are quite vulnerable to diseases, including recurrent meningitis.

Based on the results of this study, some socio-cultural factors seemed to be responsible for the recurrent transmission of epidemic Neisseria meningitidis in the study locations. For example, we identified that most women are housewives, usually with little or no formal education and unemployed, hence their inability to make informed decisions on family health. For instance, the decision to accept vaccination or when and where to seek medi-care rest essentially on the husband (men).

There seemed to be a preponderance of opinions regarding the use of alternative healthcare providers as a first referral centre. This choice was influenced by cultural practices and poor socio-economic status. Furthermore, patronage of government hospital was considered as the last resort- when the illness became severe and not amenable to alternative care.

Further, the local socio-cultural environment supports multi-dwelling housing, for instance, it is permissible for young couples to be accommodated at the family house (where the parents reside). The practice breeds over-crowding and over-stretches the available housing facilities. Multi-dwelling living pattern among close family members was widely reported in the course of our investigation in the communities surveyed. The socio-cultural practice has implications on family resilience to air-borne diseases like CSM, and general health and well-being of family or community.

The role of social mixing patterns was ascertained as a risk factor in this paper. For example, we found that even in the midst of outbreak, onion market which serves both local and international traders still opens without any form of precautionary measures.

There was a modest level of social interaction in the study areas. Most of the participants frequently engaged in social activities, such as wedding, market, burial, Islamic learning centre. These spaces were often crowded with people and often served as channels for infectious disease transmission. Previous studies or reports have also linked social mixing pattern to the spread of respiratory tract infections, including meningitis [17, 22].

Substantial progress has been made by WHO and other partners to create demand for routine and supplementary immunisation in Kebbi State [23]. Jega LGA (one of the two LGAs studied) was particularly known for non-compliance to immunisation as it was selected among the 77 LGAs that benefitted from various demand creation interventions aimed at making polio vaccines attractive and simultaneously, addressing other needs of the communities [23]. The existence of chronic non-compliance is not limited to polio immunisation (perhaps, worse with Oral Polio Vaccine) but also applicable to other routine or supplementary antigens. The social misconception came to fore during the 2015 reactive vaccination for meningitis where multiple demand creation interventions had to be instituted, even in the midst of the outbreak, to increase vaccination coverage. Non-compliance or vaccine hesitancy is an important social and communication barriers, and this has made control efforts difficult in the recent past.

We recognized the following limitations, though these might not have adversely affected the outcome of the study. Many of the participants did not understand English. Hence, translations were undertaken and might have introduced bias into the study findings. We were limited by the depth of knowledge of the participants in some aspects of the interview that are plausibly related to the recurrent transmission, for example, the role of deforestation and climate change. Further, we observed that the knowledge of the research assistants conducting the interviews seemed relatively limited and might have affected the quality of probing, and in turn, the depth of response from participants. Lastly, we did not fully explore the role of some social behaviours (e.g., smoking, going to clubs and bars) in the spread of CSM in this paper, though some of these elements are rare in the communities investigated.

Despite the limitations, we concluded that there were favourable environmental, socio-cultural and economic factors in the study areas that might have been driving recurrent epidemics of CSM. In a bid to addressing these recurrent CSM epidemics, the governments at various levels supported by health development partners can use the findings of this study to design policies and programmes targeting these factors towards complementing other preventive and control strategies.

As suggested by participants, there are potential environmental, socio-cultural and economic factors in the study area that might have been driving recurrent epidemics of cerebrospinal meningitis. In a bid to addressing this perennial challenge (recurrent seasonal CSM epidemic), governments at various levels supported by health development partners such as the World Health Organisation (WHO), United Nation Habitat and United National Development Programme can use the findings of this study to design policies and programmes targeting these factors towards complementing other preventive and control strategies.