Tropical Disease: Leptospirosis in Africa - Report Example

Tropical Disease: Leptospirosis in Africa Name Institutional Affiliation Tropical Disease: Leptospirosis in Africa Introduction There are diseases that are more prevalent to tropical regions compared to temperate regions. Tropical diseases likely occur because of the unique factors in the regions that establish favorable breeding grounds for diseases spreading vectors. These may include climatic factors such as hot temperatures, tropical rains, or ecological factors such as forests and animal transmission among others. This report focuses on Leptospirosis as a tropical disease in the Africa region. First, a description and analysis of Leptospirosis in relation to its ecological and epidemiological factors are given, by also looking at the current global burden of the diseases and standard approaches for its prevention and control in populations. Second, the ecology and epidemiology of the disease is analyzed in the context of Africa. Third, the prevention and control efforts undertaken to deal with leptospirosis in Africa are evaluated by examining their successes and failures outcomes, and the reasons for these outcomes. Fourth, the report indicates the avenues that would be more cost effective to pursue in the present and in the future for prevention and control of leptospirosis in Africa. 1. Ecology and Epidemiology, Disease Burden and Disease Preventive and Control Measures Leptospirosis is one of the common bacterial zoonoses posing global public health concerns. The ecology of leptospirosis and its transmission involves a complex interaction including presence of carrier hosts, suitability of the environment for the survival of leptospires, and the interaction between humans, animals and the environment (Lau et al., 2010). Leptospirosis is a clinical condition resulting from infection with spirochete bacteria from the Leptospira genus including L. canicola, L. Pomona, L. interrogans, L. bataviae, L. borgpetersenii, L. weilli, and L. kircheneri. Leptospires are saprophytes that thrive in hot, alkaline and humid environmental conditions and are transmitted to humans by animals, both domestic and wild (Medical News Today/MNT, 2014). The bacteria’s primary habitat is the distal tubules of the kidneys of animals. Infected animals are usually symptom-free hence only act as pathogen carriers and may excrete the bacteria into the environment continuously or once in a while (Sehgal, 2006). Rodents are the most common culprits that spread the disease, although other animal carriers for the diseases include pigs, cattle, horses and dogs and wild animals. The disease is commonly referred to as Rat Fever. Human to human transmission of the leptospires is rare. Transmission occurs via animal urine when it comes in contact with broken skin or moist surfaces such as in the mouth, nose, eyes or vagina (CDC, 2012). This occurs through drinking water contaminated by infected animal’s urine, touching soil or water contaminated by the urine of infected animals. In areas endemic with leptospirosis, the disease cause is higher during seasons of heavy rain especially if there is flooding. On the other hand, the cause of infection is distant in prevailing cold or winter conditions. The Leptospira can survive in water and soil environments for a long period of time ranging from weeks to months. The epidemiology of leptospirosis is not a straight forward model depicting transmission from animals to humans but also entails other influencers including occupational, socio-cultural, behavioral and environmental factors specific to a community, thus making its epidemiology more dynamic and complex (Lau et al., 2010). Aspects such as climatic change and increased flooding cases may increase the global incidence of leptospirosis. The disease occurs worldwide both in rural and urban areas, especially in the tropical and subtropical climate areas. People working with animals such as veterinary officers and farmers are at higher risk for being infected with leptospirosis. The risk is also high for people working in outdoor occupations such as in rice and sugar-cane fields, dairy workers, sewer workers and military staff. Recreational activities such as swimming or wading in contaminated waters also increase the risk for infection (Sehgal, 2006). In rural settings, transmission of leptospirosis is usually associated with livestock and farming with increased risk being during warm and rainy months. In urban areas, infection and transmission is associated with overcrowding, inadequate sanitation, poor hygiene standards and poverty. In developed nations, leptospirosis infection is associated with outdoor recreational exposure and tourism (Lau et al., 2010). The World Health Organization (2001) suggests that about ten million people are infected with leptospirosis annually but it is difficult to calculate death rates because they often occur in areas of the world with scarce public health services that do not routinely report majority of the death cases. Nevertheless, the death rates may range from 5% to 25% of all infected patients in the world and are much higher in poor countries than in developed nations. Areas with the highest leptospirosis incidences include Africa, China, India, Brazil, Central America, South East Asia, Caribbean, and Southern Russia. Tourist hot spots such as Hawaii, Barbados, Australia, and New Zealand, have been reported to have cases of leptospirosis infection. Although common in the tropics, leptospirosis may occur in low socio-economic parts of large non-tropical cities due to low sanitation levels. England’s health authorities reported 33 cases of leptospirosis in 2009, of which 14 were contacted when the individuals were abroad. In the same year France reported 209 cases, while Australia had reported 141 cases in 2006. In the United States, leptospirosis stopped being a reported disease in 1995 (MNT, 2014). Majority of cases infected by leptospirosis will manifest mild flu-like symptoms including chills, headache, fatigue, and muscle pain (CDC, 2012; Sehgal, 2006). Jaundice, poor appetite, panting, nose bleeds, and irregular heart beat are also other possible symptoms. If left untreated, a severe case may result leading to life-threatening conditions such as internal bleeding, meningitis, respiratory distress and organ failure. The patient may be diagnosed with Weil’s disease, at this stage which is a severe form of leptospirosis (Sehgal, 2006). An increase in the leptospirosis disease burden can be expected in areas where multiple risk factors coexist, for instance, increased flooding, rising temperatures, poor sanitation, overcrowding, abundance of rats or other animal reservoirs, and poor health care (Lau et al., 2010). The most severe impacts are likely to be witnessed in locations with already high vulnerability and poor coping mechanisms. In addition to the clinical health effects, Leptospirosis also comes with potential financial and social impacts on the victim, his family and their community. These include health care costs for the management of the acute illness, long-term medical complications, income loss, and potential impacts on long-term earning capacity. In cases where many people are infected at community level within a short span of time, enormous stress is put on health care facilities and it is also strenuous for the health system to implement public health measures for prevention, surveillance and control. Standard approaches to prevention and control in populations depends with epidemiological and risk factors. For mild situations, treatment with appropriate antibiotics as early as possible before the disease progresses is necessary. Information should be availed to public health workers and the general population regarding the disease pathophysiology and how to prevent infection. Preventive measures include control at the level of the infection source, for example through animal vaccination and rodent control (W.H.O., 2001). Rodent control can be achieved through fencing, rodent-proofing of buildings, or trapping and poisoning of vermin. Another way is to disrupt the transmission route by activities such as wearing protective gear/clothing at work, refraining from swimming in contaminated water or contact with infected animals, and provision of safe drinking water. In areas with large animal reservoirs, conduct animal surveys from time to time to enable the determination of the host and leptospires’ population and also by culturing the kidney tissue of the host animals to aid in detecting leptospiral serovars of a particular area. 2. Ecology and Epidemiology of Leptospirosis in Africa Documented data regarding leptospirosis and its burden for Africa is scarce although the disease is known to occur in the continent. The only leptospirosis incidence in Africa that has accessible published data is the 1995 to 1996 Seychelles country incidence that was estimated at 101 cases for every 100,000 persons. A recent study by Houemenou et al. (2013) confirmed the incidence to be similar in a Tanzanian population. The study also found that the highest prevalence rate was in children in below the age of 5 years and in the age group of 5 to 15 years. School children above the age of 15 years had a slightly lower prevalent rate. The rate was higher also in children compared to adults and this was explained by environmental exposures such as walking barefoot in mud, drinking or bathing in contaminated water or playing in contaminated soil environment. Leptospirosis is largely misdiagnosed because of the resemblances of its symptoms with other common conditions in humid tropical and sub-tropical regions, and it is also rarely reported because of inadequate health systems to address the condition (Biggs et al., 2013). Its impact on Africa is remains largely without documentation because majority of the communities are of poor background with limited public health facilities from which information can be shared. Also, relatively few cases are recorded in Africa because of unawareness and diagnosis difficulties in both humans and animals. However, prevailing environmental factors and socio-economic circumstances in Africa are favorable for a high prevalence of the disease in the group (Houemenou et al., 2013). Ecological factors that make Africa a potential ground for the infection and transmission of leptospirosis are many. First, Leptospirosis transmission varies depending on climatic factors such as rainfall, humidity, and temperature among others (Biggs et al., 2013). Africa lies in the tropical latitudes of the globe in which the warm and humid environment provides a thriving ground for leptospires. The leptospires’ concentration in the environment depends with seasonal cycles, which are found to be higher during the wet seasons and lower during the drier seasons (Holt, Davis & Leirs, 2006). Second, livestock density also determines the prevalence of leptospirosis with areas having larger herds or living near animal reservoirs being at higher risk for Leptospirosis transmission. The number of leptospirosis-infected animals and abundance of leptospires in the environment are both potential determinants of leptospirosis infection to Africans (Holt, Davis & Leirs, 2006). Third, urbanization in populations that are still living under low socio-economic standards are at risk for leptospirosis and this is issue facing African nations. Rodent pest populations are worsening for a larger proportion of people living in Africa due to problems associated with urbanization in terms of difficulties in providing basic standards for urbanized infrastructures including water, sewage, rat-proof housing, and rubbish collection. Usually, urban and peri-urban vermin populations increase with worsening sanitation and currently there are many urban slums growing in and around major cities of Africa (Holt, Davis & Leirs, 2006). Fourth, leptospirosis in Africa is associated with the problem of rural areas. Africa has vast rural environments in which practices such as farming intensification, deforestation and other ecological changes on the environment can change the animal species diversity, bringing people into closer contact with wild animals, and creation of voids in which stagnant water collects, leading to higher risks for leptospirosis transmission (Houemenou et al., 2013). Generally, it can be said that in addition to climatic factors, leptospirosis prevalence in Africa is also determined by socio-cultural and economic factors in which failure to afford effective public health infrastructure, poor sanitation in upcoming urban environments, increasing populations and poor farming methods are contributory factors in explaining the epidemiology of leptospirosis in Africa. 3. Prevention and Control Efforts Undertaken in Africa, Successes and Failures Rodent control is a widely used preventive and control measure for leptospirosis in Africa. The aim is to trap/bait and kill rodents in order to reduce the host-factor related with leptospirosis prevalence (Holt, Davis & Leirs, 2006). Another way is through reducing the suitability of the rodent’s habitat in order to limit their access to likely potential sites and food supplies. However, these initiatives are temporary and may be overwhelmed during high breeding seasons as dictated by climatic conditions. Also movements of people through trends such as urbanization, deforestation and farming provide further breeding grounds for the rodents. The rodent population increases with harvesting seasons because of food availability making it difficult to effectively control all the rodents. This requires improvement of food storage infrastructures as a rodent preventive or control measure. Preventing and controlling leptospirosis in Africa is also affected by low awareness of the occurrence of the disease and this is an outcome of poor economic background making it difficult to access latest information in time and develop advanced technological capabilities to deal with the problem (Machang'u et al., 2004). Diagnosis of leptospirosis is challenging in Africa as it relies on specialized knowledge, and expensive facilities and equipment. New diagnostic tools for the condition have been established but are not widely available in the African countries. Large information gaps are created in regards to not knowing the exact number of people that have contracted or died from the disease. It therefore becomes difficult to argue with policy makers that animal-transmitted diseases such as leptospirosis are a common problem (Ratzooman Project, 2006). Providing the public with new data regarding the true extent of leptospirosis is not actively encouraged by government in fear that there will be unnecessary panic and alarm. It is also difficult to conduct disease surveillance in order to justify the unknown human cost. Poor government support for public health matters also decreases the ability to effectively prevent and curb leptospirosis in Africa. Increasing awareness about the diseases in an effort to provide knowledge regarding its transmission may not be politically popular with most African countries. This is especially true in cases where conducting control initiatives such as rodent control is closely related with housing conditions, public service provision for example, water and sanitation, and active pest control activities. Generally, leptospirosis control is not always assessed for its cost-benefits, resulting in treatment failures, poor financial investments and widespread cynicism among authorities and the general public (Ratzooman Project, 2006). Generally, there lacks prioritization of public health measures for leptospirosis prevention and control in Africa and fighting leptospirosis is still an ignored cause (Biggs et al., 2013). 4. Cost-effective Avenues to Pursue Leptospirosis Prevention/Control Measures in the Present and Future Improvement of surveillance and monitoring of leptospirosis together with diagnostic capacities can be achieved cost-effectively among African countries through raising awareness about the disease. In the present, this can begin by targeting different groups of people (Biggs et al., 2013). Dialogue with communities should be established by educating the people and encouraging them to report or share information of manifestations suspected to be leptospirosis. Health workers should be trained on handling the disease in the region and education should also be included in the school curriculum for teachers and students to learn about the disease. This will require targeting the government for commitment and support in revising the future national curriculum, introducing standardized measures for surveillance, and mobilizing support for better health infrastructure and public services (Machang'u et al., 2004). It will be important for African leaders in both political, social and health realms to establish strategic partnerships at both national and international levels in order to drive research priorities and funding/sponsor opportunities regarding leptospirosis transmission. Two forms of funding can be targeted and these include bilateral funding which focuses on national priorities and multilateral funding in which priorities are set by donors (Machang'u et al., 2004). Importantly, the fight against leptospirosis will be achieved with strategies that will make various relevant sectors to work together including health, agriculture and environment; for example, in research, coordination, surveillance and legislation on ways to deal with the leptospirosis problem. Conclusion It has been found that Leptospirosis is a common ailment in the tropic regions caused by the bacteria from the Lepstospira genus that live in the kidneys of infected animals. Transmission occurs from animals to humans by direct or indirect contact with urine from infected animals through mucous membranes or broken skin. Rodents have been identified as the commonest carriers for leptospirosis pathogen transmission in African countries. In addition to climatic factors, socio-economic issues such as large populations, rural environments, slum-dwelling, livestock farming, and deforestation are unique to Africa’s leptospirosis epidemic. Attempted preventive and control measures include baiting and killing the rodents but these efforts are thwarted with scarce information regarding the spread of the disease and socio-cultural, political and economic circumstances in Africa that limit implementation of the measures. Cost-effective options include mobilizing all community stakeholders regarding ways to increase awareness of the disease, and how to prevent it, including leptospirosis education in school curriculum, improving public health infrastructure, and disease surveillance systems as well as reporting structure. References: Biggs, H., Hertz, J., Munishi, M., Galloway, R., Marks F., Saganda, W., Maro, V., and Crump, J. (2013). Estimating leptospirosis incidence using hospital-based surveillance and a population-based health care utilization survey in Tanzania. PLoS Neglected Tropical Diseases, 7(12) e2589. CDC/Centers for Disease Control and Prevention. (2012). Leptospirosis. CDC. Retrieved October 23, 2012 from http://www.cdc.gov/leptospirosis/infection/index.html. Holt, J., Davis, S. & Leirs, H. (2006). A model of leptospirosis in an African rodent to determine risk to humans: seasonal fluctuations and the impact of rodent control. Acta Tropica, 99, 218-225. Houemenou, G., Ahmed, A., Libois, R., & Hartskeerl, R. (2013). Leptospira spp. prevalence in small mammal populations in Cotonou, Benin. Epidemiology, 1-8. Lau, C., Smythe, L., Craig, S., & Weinstein, P. (2010). Climate change, flooding, urbanization and leptospirosis: Fuelling the fire? Transactions of the Royal Society of Tropical Medicine, 104, 631-638. Machang'u, R.S. Mgode, G.F. & Assenga, J. (2004). Serological and molecular characterization of Leptospira serovar Kenya from captive African giant pouched rats (Cricetomys gambianus) from Morogoro Tanzania,” FEMS Immunology and Medical Microbiology, 41(2) 117–121. Medical News Today/MNT. (2014). What is leptospirosis? What causes leptospirosis? Retrieved October 20, 2014 from http://www.medicalnewstoday.com/articles/246829.php Ratzooman Project (2006). Rats and human health in Africa: Proceedings of an international workshop on rodent-borne diseases and the RatZooman research project. South Africa: University of Greenwich. Sehgal S., C. (2006). Epidemiological patterns of leptospirosis. Indian Journal of Medical Microbiology, 24, 310-1. W.H.O. (2001). Water-related diseases: Leptospirosis. WHO, Water Sanitation Health, Retrieved October 22, 2014 from http://www.who.int/water_sanitation_health/diseases/leptospirosis/en/ Read More