Tremendous success in control of vector borne infections like Trypanasomiasis was scored in the previous decades (20th century). This later led to laxity resulting in prioritization of prevention and control of other infections. Re-emergence of vector borne zoonoses has occurred, due to change in global trends (Population growth, uncontroled movement, climate).

1. Uganda, a hotspot for neglected
vector borne zoonoses
Joseph M Kungu and Halid.Kirunda

2. Vector-borne zoonoses
 Tremendous success in control of vector borne infections
e.g Trypanasomiasis was scored in the previous decades
(20th century).
 This later led to laxity resulting in prioritization of prevention
and control of other infections.
 Re-emergence of vector borne zoonoses has occurred, due
to change in global trends (Population growth, uncontroled
movement, climate.

3. Human host
 Zoonotic vector-borne infections are responsible for a
considerable proportion of human deaths (1.4/annum),
with most impact felt in Africa.
They are prominent contributors to emerging diseases,
globally.

4. Animal hosts
 Direct effects of such infections have been underestimated
in animals. The indirect role the animals play in harboring
the pathogens can’t be undermined.
 Very few of these conditions are among the diseases
priority for control in developing countries.

5. Importance of vectors
 The ability of vectors to bridge spatial and ecologic gaps
between animals and humans increases opportunities for
emergence. These barriers are not only spatial but behavioral
and ecological e.g yellow fever transmision.
 Small adaptations of a pathogen to a vector can have
profound effects on the rate of transmission to hosts.

6. Importance of vectors
 The complexity of vector transmission offers the pathogen
increased opportunities to evolve. In almost no instances is
the arthropod simply a vessel for transmission.

7. Cont’d
 The pathogen replicates in some fashion, which makes it dependent
on an invertebrate host physiology much different from what it will
encounter in its various vertebrate hosts.
 As a consequence, epidemic emergence can result from enhanced
transmission independent of increased pathogenicity to humans.
 This is especially true of arboviruses that have high potential
mutability.

8. Role of the environment
 Ecosystems provide conducive ground for maintaining
transmission cycles of vectors and pathogens.
 They regulate spillover into human and animal populations.
 Human activities that alter natural ecosystems also affect
the transmission cycles of vector-borne infectious diseases.

9. Situation in Uganda
 The neglected vector-borne infections of major public
health and socio-economic importance in Uganda are HAT,
schistosomiasis, lymphatic filariasis (LF) and
onchocerciasis.
 Others like leshmaniasis, WestNile Virus disease, Dengue,
Crimean Congo, occur but their importance goes
unnoticed.

10. Situation in Uganda
Parasite Disease Agent Affected areas Burden
Protozoa Visceral Leishmaniasis
(Kala-Azar)
Leishmania donovani Pokot County,
Nakapiripirit
district
(NE Uganda)
Unknown;
> 400 cases treated
per year, 70%
from Kenya
Human African
Trypanosomiasis
Trypanosoma
gambiense
NWUganda,predominantly in
Adjumani, Moyo,
Arua & Yumbe
district
In 2004, 354 cases
were reported
T. rhodesiense SE and E Uganda In 2005, 154 cases
and 7 deaths were
reported
Viruses RVF, Yellow fever,
Dengue, Crimean Congo,
WestNiile , Sunguru,
Bukakata.
ARBOViruses Uganda
Helminths Lymphatic filariasis
(Elephantiasis)
Wuchereria bancrofti North of Victoria
Nile and in W
Uganda
54 districts, 14.6million at risk
0.4 – 32.9%
prevalence
Onchocerciasis
(River Blindness)
Onchocerca volvulus 21 districts; highly
endemic in West
Nile region, central
shores of Lake
Albert, Mt Elgon
& foci in SW
Uganda
35 district, > 3.8 million at risk
1.5million affected.
Schistosomiasis
(Bilharziasis)
Schistosoma
haematobium
S. mansoni 38
Districts on
northern shores of
Lake Kyoga districts
73 districts ,Approx. 4 million
cases
16.4 million at risk

11. Control strategy
Intervention Control output Agent targeted
Community education behavioral change All infections
Evironmental
management
To limit the natural
habitats
Vectors
Residual spraying Kill vectors Vectors of filariasis ( pyrethroids,
organophosphates,)
, leishmaniasis (carbamates), malaria
(DDT)
Insecticide treated
nets
Prevent bites Vectors
Traps Depopulate vectors Trypanasomiasis
Vaccination Prevention of infection Yellow fever
Improve sanitation Limit the transmission
cycle
Schistosomiasis

12. What are challenges encountered?
 Complexity of epidemiology and adaptive plasticity of
pathogen and arthropod make the vector-borne diseases
difficult to control, much less to eradicate.
 Vaccines are unavailable for all but a few diseases; and
even when they are available, as for yellow fever,
prevention can be difficult to achieve.

13. Cont’d
 Development of resistance of pathogens to treatment e.g
P. falciparum, and treatment for visceral leishmaniasis
remains too expensive and complicated to be widely
practiced where it is most needed.
 The constant development of pesticide resistance.
 Even when pesticides are efficacious, their effectiveness is
often compromised by human behavior and vector biology,
policies on use e.g DDT.
 Changes in climate, land use, and transport have affected
rates of pathogen emergence in ways poorly understood.

14. Way forward
Research needed in;
 The biology and ecology of the vectors and pathogens.
 The presence, distribution and abundance of the vectors
and pathogen host populations.
 The environmental, climatic, ecological and topographic
conditions of relevance to vector ecology .
 Risk assessment to indicate the areas at highest risk of
introduction of a vector that is unlikely to be present.

15. Conclusion
Vector-borne infections are a result of poverty
and have increased poverty levels in
developing countries.
Actions to reduce vector-borne diseases will
relieve expenses, hence saving for well-being
and development of Uganda.

16. Acknowledgements
 Dr. Lutwama, UVRI
 Dr. Edrinah Muheki, Wamboka, Moses Adriko of the Vector
Control Division.
 Dr.Winyi Kaboyo, MOH

17. THANK YOU
God bless you in Jesus name
Ecclesiastes 12.12-14