Africa Wild

Blowflies as vectors of Bacillus anthracis in the Kruger National Park
Anthrax, caused by Bacillus anthracis, is endemic in the Kruger National Park (KNP).
The epidemiology of B. anthracis is dependent on various factors including vectors.
The aims of this study were to examine non-biting blowflies for the presence of B. anthracis
externally and internally after feeding on an anthrax-infected carcass and to determine the role
of flies in disseminating B. anthracis onto the surrounding vegetation.
During an anthrax outbreak in 2014 in the endemic Pafuri region, blowflies associated with
two 2–3-day-old anthrax-positive carcasses (kudu and impala) as well as surrounding
vegetation were collected and investigated for the presence of B. anthracis spores.
The non-biting blowflies (n = 57) caught included Chrysomya albiceps, Ch. marginalis and Lucilia
spp. Bacillus anthracis spores were isolated from 65.5% and 25.0% of blowflies collected from
the kudu and impala carcasses, respectively.
Chrysomya albiceps and Ch. marginalis have the potential to disseminate B. anthracis to vegetation
from infected carcasses and may play a role in the epidemiology of anthrax in the KNP. No
B. anthracis spores were initially isolated from leaves of the surrounding vegetation using
selective media. However, 170 and 500 spores were subsequently isolated from Abutilon
angulatum and Acacia sp. leaves, respectively, when using sheep blood agar.
Conservation implications: The results obtained in this study have no direct conservation
implications and only assist in the understanding of the spread of the disease.

Richprins wrote: ↑Fri May 15, 2020 6:21 pm It comes every few years when there is drought!

In KNP, outbreaks were usually associated with the driest
periods of the year (winter and early spring) or during
climatic dry cycles (Pienaar 1967). However, since the 2010
outbreak onwards, outbreaks mainly occurred in wet
periods (summer months; E.H. Dekker [Skukuza State
Veterinary Office] pers. comm., 2014). This is of importance
as insect activity and abundance on a carcass is influenced
by climate. In the rainy season, the insect abundance
(especially the blowflies) will increase, which was speculated
by Braack (1985) to increase B. anthracis dissemination by
blowflies to vegetation during an outbreak.

Richprins wrote: ↑Sat May 16, 2020 10:00 am Klippies!

I spoke to Dr de Vos and basically Kruger's roan are at the very edge of their natural range and prefer relatively open country. So the biggest reason for their decline has probably been bush encroachment.