Table 1.
Qualitative estimation of the impact of zoonotic arboviral diseases with a non-zero likelihood of evolving in response to animal trade, animal migration and climate change.
| Arbovirus | Chances for dispersal | Major mode of dispersal | Chances for establishing new endemic foci (c) | Chances to be eliminated again (d) | Impact on public health (e) | Impact on veterinary public health (e) | Occurrence and distribution influenced by climate (f) |
|---|---|---|---|---|---|---|---|
| WEEV | Moderate | Long distance (viremic birds) | Moderate to high | Low to moderate | Low | Low | Yes |
| EEEV | Moderate | Long distance (viremic birds) | Moderate to high | Low to moderate | Low | Low | Yes |
| VEEV | Moderate to high (a) | Short distance (mosquitoes, rodents) | Moderate | Low to moderate | Low | Low to moderate (a) | Yes |
| WNV | Moderate to high | Long distance (viremic birds) | Moderate to high | Zero to low | Moderate to high | Low | Yes |
| JEV | Moderate | Long distance(viremic birds) | Moderate | Low to moderate | Moderate to high | Low to moderate | Yes |
| RVFV | Moderate to high | Short to long distance (livestock animals) | Moderate to high | Low to moderate | Moderate | Moderate to high | Yes |
| USUV | Moderate to high | Long distance (viremic birds) | Moderate to high | Zero to low | Negligible | Low | Yes |
| TBEV | Low to moderate | Short distance (ticks, rodents) (b) | Moderate to high | Zero to low | Low | Negligible | Yes |
| POWV | Low to moderate | Short distance (ticks, rodents) (b) | Moderate to high | Zero to low | Low | Negligible | Yes |
(a) = Depending on the VEEV subtype involved.
(b) = When ticks are attached to birds, the respective viruses can as well be carried over long distances.
(c) = Because the mechanisms allowing a successful establishing of new endemic foci are poorly understood, the estimates provided are speculative despite for the viruses where this happened in recent history, e.g. WNV in America. Expansion of the geographic range of tick-borne TBEV and POWV mainly occurs on a different scale than with mosquito-borne arboviruses.
(d) = The general rule "the earlier the detection of the alien virus, the better the chance to successfully terminate it" applies for both mosquito- and tick-borne viruses, but due to the life cycle of mosquitoes and the availability of efficient larvicides and adulticides, their abundance can be better addressed with an integrated pest management and mosquito control program than fighting ticks in a tick habitat.
(e) = TBEV and JEV cause diseases in humans that can be prevented by applying safe and efficient vaccines. There is an inactivated vaccine available for the three equine encephalitis viruses and WNV.
(f) = The distribution of all arboviruses depends to a major part of the abundance of suitable vector species. Since their life cycle is strongly influenced by the weather, climate is an important issue in the occurrence and spread of arboviruses.