| Sumario: | Q fever is a zoonotic disease caused by the intracellular bacterium Coxiella burnetii. It
was first described in 1935. Ruminants are considered to be the primary source of infection to
humans who become infected through inhalation of aerosols from infected ruminants and also
through exposure to animal products such as unpasteurized dairy products. Clinical disease in
animals is characterized by abortion and still births in sheep and goats while in cattle there is
infertility and mastitis. In humans the disease syndrome can be divided into acute and chronic
forms with the acute form manifesting as a relatively mild self-limiting febrile illness while the
chronic form is a more severe disease characterized by hepatitis, pneumonia and chronic fatigue.
This disease is therefore important due to its public health implications in humans and
reproductive losses in animals.
There are reports on the occurrence of this disease in Kenya, though very few studies
have been published recently on the epidemiology of the disease and specifically in pastoral
communities where livestock is the main source of livelihood. This study was therefore designed
with the following objectives 1) To assess the knowledge, attitude and practices of the livestock
owners in relation to Q fever and its control in Bura, Tana River County; 2) To estimate the
seroprevalence of Q fever in livestock and humans in the study area; and 3) To determine the
risk factors associated with the disease in livestock and humans. A seroepidemiological study
was therefore carried out using an ELISA test to determine the occurrence of Coxiella burnetii
antibodies in livestock (cattle sheep and goats) and humans in Bura, Tana River County.
Questionnaires were also administered to household heads to determine the risk factors for Q
fever. The prevalence of Coxiella burnetii antibodies in all animals surveyed was 13% (95% CI,
6.41-19.59%). The seroprevalence was higher in goats at 16% (95% CI, 8.81-23.19%) compared
to sheep at 12% (95% CI, 5.63-18.37%) and cattle at 5.2 %, (95% CI, 0.85-9.55%). There were
no statistically significant differences in the seroprevalence of Coxiella burnetii antibodies
between animals sampled within the irrigation scheme versus those sampled within the
manyattas at 12% (95% CI, 5.63-18.37%) and 14% (95% CI, 7.20-20.80%), respectively.
Factors associated (P<0.05) with animal seropositivity were species, age and sex of the animal.
Compared with adults, weaners were less likely to be seropositive (OR, 0.102; P= 0.002). With
regard to species, goats were more likely to be seropositive compared to cattle (OR, 3.49;
P=0.01).
Two-hundred-and seventy-two humans were screened for antibodies against Coxiella
burnetii. The seroprevalence of Coxiella burnetii was 26.8% (95% CI, 18.12-35.48%). The
difference in the seroprevalence of Coxiella burnetii in individuals sampled within the irrigation
scheme at 30.2% (95% CI, 21.20-39.20%), and those sampled in the non-irrigated areas at 16.4%
(95% CI, 9.14-23.66%), was statistically significance. The seroprevalence for Coxiella burnetii
among adults, children and adolescents was 34.2% (95% CI, 24.90-43.50%), 26.8% (95% CI,
18.12-35.48%) and 23.2% (95% CI, 14.93-31.47%), respectively. With regard to sex, there were
slight differences in the seroprevalence of Coxiella burnetii among males and females occurring
at 28% (95% CI, 19.20-36.80%) and 26% (95% CI, 17.40-34.60%) respectively.
There were differences in the seroprevalence between different occupation groups with
higher frequencies being reported amongst herdsmen and farmers at 42.9% (95% CI, 33.20-
52.60%) and 30.2% (95% CI, 21.20-39.20%), respectively. This difference was not significant.
Sixteen percent (95% CI, 8.81-23.19%) and 11.8% (95% CI, 5.48-18.12%) of the individuals reported having experienced malaria and flu like symptoms within a period of two months before
the study begun out of which 39.5% (95% CI, 29.92-49.08%) and 25% (95% CI, 16.51-33.49%)
were seropositive for Coxiella burnetii antibodies, respectively. Risk factors associated (P<0.05)
with individual and household seropositivity were occupation, irrigation status and animals
housing within the family house (P<0.05).
In the questionnaire survey, the respondents were neither aware of Q fever nor its risk
factors. The only risk factor associated with Coxiella burnetii seropositivity was housing of
animals within the family house whose odds were two times higher compared to households who
did not house their animals within their living house.
The present study confirmed the occurrence of Coxiella burnetii in the study area. The
high prevalences in both the livestock and humans sampled may have been due to the low levels
of awareness on this condition and the subsequent lack of control measures. Land use change to
irrigation may also have increased the risk of infection especially in the human population. It is
therefore necessary to employ appropriate strategies for diagnosis of Q- fever patients by
equipping local and national laboratories and increasing the knowledge of physicians of potential
clinical signs of the disease and how to make a diagnosis of the same. Community education and
awareness creation would also be very helpful in preventing Q -fever infection. There is
therefore need for the government to have control strategies for the disease such as introduction
of vaccination which is currently not being carried out in the country. Further research to
determine the effect of land use change on tick-borne diseases in Kenya should also be carried
out.
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