Limiting the northerly advance of Trypanosoma brucei rhodesiense in post conflict Uganda
View/ Open
Date
05/07/2011Author
Selby, Richard James
Metadata
Abstract
In October 2006 an intervention was initiated to arrest the northerly advance through Uganda
of the zoonotic parasite Trypanosoma brucei rhodesiense. This is a protozoal infection that
is vectored by the tsetse fly. It is the aim of this thesis to review the impact of this large scale
treatment programme in terms of animal health and human disease.
The Stamp Out Sleeping Sickness (SOS) campaign was designed to target the cattle reservoir
of T. b. rhodesiense in these newly affected areas by block treating >180,000 head of cattle.
This was achieved in collaboration with final year vet students from the University of
Makerere, Uganda. Farmers were also encouraged to spray their animals with deltamethrin in
order to suppress the tsetse population.
In order to monitor the impact of this intervention a base line survey was carried out.
Evaluation of the logistics and implementation of the SOS campaign was assessed through
interviews with personnel involved. Analysis by PCR revealed the prevalence of T. brucei
s.l. as 15.57% (T. b. rhodesiense as 0.81%) within the cattle reservoir prior to SOS treatment.
Follow up sampling was carried out at 23 locations at three, nine and 18 months. The
prevalence of T. brucei s.l. was reduced post treatment, but in the absence of sustained vector
control infections amongst the animals returned by nine months and subsequently exceeded
the base line findings (P=<0.0001).
It was observed that across most of the SOS area, T. b. rhodesiense did not re-establish
following treatment. However, a significant cluster was identified where cases of both
human and animal disease were continually reported. This cluster was noted to include the
area immediately surrounding the Otuboi cattle market.
This link between cattle movement and the spread of T. b. rhodesiense is an established one
and is addressed by Ugandan governmental policy which states that ‘cattle traded at market
must be treated with trypanocidal drugs prior to movement’. The findings presented here
suggest that this policy may not be strictly enforced. The risk of spread is compounded at the
northern districts of Uganda restock their domestic livestock following years of civil conflict.
The majority of animals are traded in a northward direction – transporting infected animals
from the endemic south. The scale of this trade is assessed through questionnaires, analysis
of trade records and animal screening. Specific consideration is given to the implications of
this cattle trade and impact this may have on the sustainability of the SOS campaign.