Seasonal Changes in Vegetation and Land Use in Lassa-Fever-Prone Areas (Kenema and Kailahun Districts) in Eastern Sierra Leone

Abstract

Lassa Fever is endemic to the eastern region of Sierra Leone. It is a haemorrhagic disease that is often transmitted from rats to humans and then human to humans. Ecological disturbances such as changes in land use involving conversion of natural ecosystems to agriculture, mining or for urban expansion are reported to bring humans into close contact with animals such as the Mastomys rat that carries the Lassa Fever virus thereby posing health problems.The nature and extent of such ecological disturbances or land use changes within areas known to be endemic to Lassa Fever are not clearly understood from a research context in Sierra Leone. This study was therefore undertaken to identify the pattern of changes in land use and cropping practices and their potential to bring humans into close interactions with the Mastomys rat that is the host for the Lassa Fever virus. Four communities were chosen for the study, two rural (Lalehun and Majihun) and two urban (Lambayama section in Kenema City and Largo Square section in Segbwema Town). Different vegetation and land use/cropping practices were identified and observations were made on the pattern of changes at different times in the cropping year. There were four common vegetation and cropping practices found in all communities: upland rice intercropping, old fallow, young fallow, and swamp rice cultivation. The study revealed the variations in land use patterns and cropping practices between urban and rural settlements. Agro-forestry practices such as perennial cash crops cacao and rubber plantations were more common in rural communities. The study also revealed that while fallow vegetation persisted in rural areas there had been expansion of settlements into old fallow vegetation indicating a greater threat to the persistence of natural ecosystem in urban than in rural settlements. These disturbances resulted in habitat fragmentation and increased the likelihood of contact between humans and animal species (e.g. Mastomys rat) associated with various habitats.