Marburg virus has been recovered from Egyptian fruit bats Rousettus aegyptiacus in West Africa. An epidemic of a very deadly disease, Marburg hemorrhagic fever, is brewing in West Africa. Or maybe not. When zoonotic diseases spillover from wildlife into people it can be very difficult to tell whether what we observe is a singular event, one off and unlikely to lead to anything, or the tip of an iceberg.
A few days later, Front Page Africa reported that a second person had been infected. The circumstances of their infections have not been reported. However, it would not be surprising if the original infection resulted from contact with an Egyptian fruit bat Rousettus aegyptiacus , a species that is a known reservoir of Marburg virus.
What is a little surprising is that the cases arose in West Africa. The numbers of ERBs captured at each site are shown below the cave name. The Ebola control systems in place in Guinea and in neighbouring countries are proving crucial to the emergency response to the Marburg virus. Marburg is transmitted to people from fruit bats and spreads among humans through direct contact with the bodily fluids of infected people, surfaces and materials.
Illness begins abruptly, with high fever, severe headache and malaise. Many patients develop severe haemorrhagic signs within seven days. Neonates were observed occasionally in March and April, outside the birthing season, suggesting asynchronous births.
In previous studies, the Egyptian rousette bat population in Matlapitsi Cave was estimated to fluctuate from 3, to 9, bats, with the lowest numbers occurring during the winter months Figure 1. Numbers in parentheses indicate number of bats sampled per month. Of 1, bats tested, In total, Seroconversion was detected in 12 The bats that seroconverted were all juvenile bats on first capture Table 1. Of the liver-spleen tissue pools tested, 3 1. Figure 2. Phylogenetic tree of partial MG and complete nucleic MG was closely related to the Ozolin strain Only 22 aa substitutions were identified between these 2 viruses, which were isolated 38 years apart.
Matlapitsi Cave, a m hike from the main road running through the rural community of Fertilis, is accessible to humans. The cave was used in the past for religious practices and circumcision rituals, which have since been discontinued.
In spite of their discontinuation, we found human shoe prints, litter, and signs of recent fire pit use at the cave entrance during our sampling trips. Informal discussions with persons of the local communities indicated that bats were not being hunted and their meat was not being consumed by local residents.
However, uncontrolled migration of persons from neighboring countries where bat meat is consumed and increasing economic pressures, which could force local persons to hunt wildlife, might put the population at increased risk for MVD.
Observations made in this study confirm a distinctly seasonal Egyptian rousette bat reproductive period as previously reported Gradual loss of passive immunity increases the number of susceptible bats, thus creating suitable conditions for MARV spread in the colony.
Results of our study suggest that the single but relatively long birthing season complemented by asynchronous births and potential migration of bats might contribute to sustained annual MARV circulation in this area These findings appear to be in contrast with those from the study in Uganda, which indicated that 2 yearly birthing seasons were required to maintain circulation of MARV in Egyptian rousette bats The period of lowest seropositivity in young bats April—July might indicate a period of increased risk for exposure and shedding.
The MARV sequence from the Matlapitsi Cave is phylogenetically most closely related to the Ozolin MARV strain, suggesting this variant has persisted in the southern part of Africa relatively unchanged since first discovered in 3.
These findings contribute to our knowledge of MARV ecologic factors that could lead to a zoonotic spillover into humans and, thus, assist in the development of evidence-based policies for MVD risk reduction in South Africa.
Diagnostic capacity to test for these types of viruses is also lacking. The same is true for detecting disease in humans especially when only a few cases occur and in very remote areas. From our knowledge of the epidemiology of the virus, it will be present wherever this bat species occurs. Environmental and man-made changes act as a significant contributor to disease emergence. These include changes in land use, human population growth and increased mobility across landscapes, changes in human socioeconomic behaviour or social structure, increased trade, forest fires, extreme weather events, wars, and breakdown in public health infrastructure, to name a few.
These activities also result in increased contact with wildlife such as bats, ultimately leading to a higher risk of spillover. The Egyptian Rousette bat will also use abandoned mines as roosting sites and this may change their distribution.
This is also true for Marburg virus. More opportunities for contact between bats and humans will certainly lead to an increase in human infections.
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