Courtesy : Bachelor of Science Forestry (Botany, Zoology, forestry)
Health effects
Public health context
The degradation and loss of forests disrupts nature’s balance. Indeed, deforestation eliminates a great number of species of plants and animals which also often results in an increase in disease, and exposure of people to zoonotic diseases. Deforestation can also create a path for non-native species to flourish such as certain types of snails, which have been correlated with an increase in schistosomiasis cases. # ISO certification in India
Forest-associated diseases include malaria, Chagas disease (also known as American trypanosomiasis), African trypanosomiasis (sleeping sickness), leishmaniasis, Lyme disease, HIV and EbolaThe majority of new infectious diseases affecting humans, including the SARS-CoV2 virus that caused the current COVID-19 pandemic, are zoonotic and their emergence may be linked to habitat loss due to forest area change and the expansion of human populations into forest areas, which both increase human exposure to wildlife. # ISO certification in India
Deforestation is occurring all over the world and has been coupled with an increase in the occurrence of disease outbreaks. In Malaysia, thousands of acres of forest have been cleared for pig farms. This has resulted in an increase in the zoonosis the Nipah virus. In Kenya, deforestation has led to an increase in malaria cases which is now the leading cause of morbidity and mortality the country.A 2017 study in the American Economic Review found that deforestation substantially increased the incidence of malaria in Nigeria. # ISO certification in India
Another pathway through which deforestation affects disease is the relocation and dispersion of disease-carrying hosts. This disease emergence pathway can be called “range expansion”, whereby the host’s range (and thereby the range of pathogens) expands to new geographic areas. Through deforestation, hosts and reservoir species are forced into neighboring habitats. Accompanying the reservoir species are pathogens that have the ability to find new hosts in previously unexposed regions. As these pathogens and species come into closer contact with humans, they are infected both directly and indirectly. # ISO certification in India
A catastrophic example of range expansion is the 1998 outbreak of Nipah virus in Malaysia.For a number of years, deforestation, drought, and subsequent fires led to a dramatic geographic shift and density of fruit bats, a reservoir for Nipah virus.Deforestation reduced the available fruiting trees in the bats’ habitat, and they encroached on surrounding orchards which also happened to be the location of a large number of pigsties. The bats, through proximity spread the Nipah to pigs. While the virus infected the pigs, mortality was much lower than among humans, making the pigs a virulent host leading to the transmission of the virus to humans. This resulted in 265 reported cases of encephalitis, of which 105 resulted in death. This example provides an important lesson for the impact deforestation can have on human health.
Another example of range expansion due to deforestation and other anthropogenic habitat impacts includes the Capybara rodent in Paraguay This rodent is the host of a number of zoonotic diseases and, while there has not yet been a human-borne outbreak due to the movement of this rodent into new regions, it offers an example of how habitat destruction through deforestation and subsequent movements of species is occurring regularly. # ISO certification in India
A now well-developed and widely accepted theory is that the spillover of HIV from chimpanzees was at least partially due to deforestation. Rising populations created a food demand, and with deforestation opening up new areas of the forest, hunters harvested a great deal of primate bushmeat, which is believed to be the origin of HIV. # ISO certification in India
Research in Indonesia has found that outdoor workers who worked in tropical and deforested instead of tropical and naturally forested areas experienced cognitive and memory impairments which appear to be caused primarily by exposure to high heat which trees would have protected them from. Deforestation reduces safe working hours for millions of people in the tropics, especially for those performing heavy labour outdoors. Continued global heating and forest loss is expected to amplify these impacts, reducing work hours for vulnerable groups even more. # ISO certification in India
