I believe the condition is infestation. Infestation is the state of being invaded or overrun by pests or parasites. It can also refer to the actual organisms living on or within a host. For example being invaded by ectoparasites such as lice, mites, or ticks. It may also refer to the presence of an unusually large number of insects or animals in a place, typically so as to cause damage or disease.
The primary greenhouse gases in Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide and ozone. Without greenhouse gases, the average temperature of Earth's surface would be about −18 °C (0 °F), rather than the present average of 15 °C (59 °F).
If the animal or the organism is unborn or not correct with it's body (like incomplete metamorphosis) it could effect their behavior and their way of walking,drinking,eating,sleeping,or even speaking or making sounds.