Abstract:
Arboviruses are among emerging pathogens of public and veterinary
health significance. However, in most of sub-Saharan Africa, their role in the aetiologies
of diseases in farm animals is poorly described due to paucity of active surveillance
and appropriate diagnosis. Here, we report the discovery of a previously unknown orbivirus
in cattle collected in the Kenyan Rift Valley in 2020 and 2021. We isolated the virus
in cell culture from the serum of a clinically sick cow aged 2 to 3 years, presenting signs
of lethargy. High-throughput sequencing revealed an orbivirus genome architecture
with 10 double-stranded RNA segments and a total size of 18,731 bp. The VP1 (Pol) and
VP3 (T2) nucleotide sequences of the detected virus, tentatively named Kaptombes
virus (KPTV), shared maximum similarities of 77.5% and 80.7% to the mosquito-borne
Sathuvachari virus (SVIV) found in some Asian countries, respectively. Screening of
2,039 sera from cattle, goats, and sheep by specific RT-PCR identified KPTV in three
additional samples originating from different herds collected in 2020 and 2021.
Neutralizing antibodies against KPTV were found in 6% of sera from ruminants (12/
200) collected in the region. In vivo experiments with new-born and adult mice
induced body tremors, hind limb paralysis, weakness, lethargy, and mortality. Taken
together, the data suggest the detection of a potentially disease-causing orbivirus in
cattle in Kenya. Its impact on livestock, as well as its potential economic damage,
needs to be addressed in future studies using targeted surveillance and diagnostics.
IMPORTANCE : The genus Orbivirus contains several viruses that cause large outbreaks
in wild and domestic animals. However, there is little knowledge on the contribution
of orbiviruses to diseases in livestock in Africa. Here, we report the identification of a
novel presumably disease-causing orbivirus in cattle, Kenya. The virus, designated
Kaptombes virus (KPTV), was initially isolated from a clinically sick cow aged 2 to 3 years,
presenting signs of lethargy. The virus was subsequently detected in three additional
cows sampled in neighboring locations in the subsequent year. Neutralizing antibodies
against KPTV were found in 10% of cattle sera. Infection of new-born and adult mice
with KPTV caused severe symptoms and lead to death. Together, these findings indicate
the presence of a previously unknown orbivirus in ruminants in Kenya. These data are
of relevance as cattle represents an important livestock species in farming industry and
often is the main source of livelihoods in rural areas of Africa.
Description:
DATA AVAILABILITY : The sequences of this study can be found under the GenBank accession numbers
KPTV B215 genome OQ122118 to OQ122127, as well as fragments of S2 of KPTV B97, KPTV B215, KPTV
B128, and KPTV B364 under the accession numbers OQ122128 to OQ122131, respectively.