Question

It if often said that a change in ecology is contributing to the re-emergence of infectious diseases. What kinds of changes are occurring?

Be able to differentiate between the different levels of ecology – population, community, ecosystem, etc. and identify ways in which each can be used to understand disease.

How can Chagas, Malaria, cholera, Lyme, Leptospirosis, and Zika be studied from an ecological perspective? What are some ways that each can be influenced by environmental factors?

What is the importance of niche to the study of infectious diseases? How are mosquitoes an example?

Answer 1

1- The changing environmental conditions are often associated with bringing new ecological conditions. The temperature variation, climate change, effect on local climate has caused variations and has supported some selective species to survive and get adapted to these slow and steady changing environment. Human intervention has caused to help the reemergence of diseases as they have disturbed the balance of the natural ecosystem due to their intervention in natural processes. Anthropogenic environmental change on the diversity, distribution, abundance and transmission of parasites and pathogens into the environment. The overfishing has led to a disturbance in the aquatic lives, using trawl nets have eroded the phytoplankton from the sea bed destroying the most photosynthetically active species and the energy houses for the planet. Due to such activities which are carried for self-benefits humans have pushed ecological to a level where it is supporting the rise of diseases. the zoonoses-pathogens especially. There is still considerable uncertainty as to how the mechanism of anthropogenic activity favours the parasitic diseases to come into play but still, the effect is noticed.

Chagas, Malaria, cholera, Lyme, Leptospirosis, and Zika be studied from an ecological perspective can be linked to ecological conditions as hurricanes, cyclone, heat waves, deforestation, floods and land burning can help these pathogens choose a suitable environment for their growth and multiply to increase their population. Niche study is important as it is the main functioning zone of the organism. Mosquitoes have found a good way to survive in both clean and murky waters. The spread of Malaria despite vaccination has failed to be eradicated from the countries which cannot provide sanitation facilities.

Certain examples can be sited for disease occurrence due to ecological imbalance:

1-Lyme disease outbreaks: deforestation, reforestation and habitat fragmentation resulting in increase preference of reservoir population infection and higher contact with infected vectors.

2-Ebola virus outbreaks: direct contact between infected animals, meat, or contaminated fruits.

3-Heavier rainfall is associated with enhanced Toxoplasma gondii oocyst dynamics and distribution.

4- The Increased minimum temperature associated with an increase in malaria incidence in Papua New Guinea with differing lag times according to different regions (local scale).