| dc.description.abstract | Flu-like diseases that present with non-specific symptoms pose big diagnostic
problems to clinicians. Brucellosis, malaria, typhoid, streptococcal infections and
rheumatism, which are in this category, were studied to gather characteristic data that
could aid in their differential diagnosis. The study was conducted in Narok District, a
typical pastoral region in Southern Kenya bordering Tanzania, where cultural,
environmental and economic conditions allow these diseases to be prevalent. Specific
study centres were the District hospital and three outlying dispensaries Mararianta,
Siyapei and Olasiti. These centres were selected because they were better equiped and
easily accesible. Patients sampled in these health units were also representative of the
reference population.
Brucellosis, a worldwide zoonosis that causes great economic losses, has not been
diagnosed much in humans in Kenya and especially Narok District. However, recently
created awareness in the region has caught the attention of some clinicians who are now
testing for brucellosis although the vast majority of health centres do not. Brucellosis
patients who are not tested are mostly treated for other diseases, mainly malaria. Malaria
is a major differential of brucellosis and is present in Narok to a great extent (prevalence
of 68%; Muriuki, 1994). In most health units without laboratory facilities and where
clinicians make diagnosis by elimination method, febrile patients have been treated for
malaria as a first priority. This procedure, although desirable under the circumstances,
masks other flu-like diseases which are also febrile. In this study, flu-like patients were
sampled and studied prospectively, subjecting them to a series of tests for
brucellosis(Rose-bengal plate test, Serum agglutination test, complement fixation test),
malaria(Blood smear test), typhoid(Widal test), streptococcal infections(Anti-Streptolysin
o test) and rheumatic fever (Rheumatoid factor test). Results showed that brucellosis,
typhoid and malaria are common in Narok, and their respective prevalences were 12%,
40% and 9%. Previously, both brucellosis and typhoid have been underdiagnosed
(estimated prevalence from hospital records was 0.02 and 0.03 respectively). Clinicians
did not think that streptococcal infections existed in the District, yet 48 (9.8%) patients
were positive on antistreptolysin-O test and 28 (5.7%) were positive on rheumatoid factor
test.
Findings in this study show that accurate clinical diagnosis of these diseases is
difficult. Flu-like symptoms such as headache, fever, joint pains, unspecific body pains,
sweats, chills and abdominal discomfort showed a low positive predictive value but a
high negative predictive value. They could not be relied on to increase the likelihood of a
positive test since their Odds Ratio's were statistically insignificant. When the patients
were subjected to laboratory tests, the post-test probability of disease rose significantly. It
is therefore necessary to subject flu-like patients to the screening tests such as those used
in this study. They are simple and increase the likelihood of a correct diagnosis. Patients
who were diagnosed as having brucellosis also showed a lot of mixed infections,
especially typhoid and streptococcal infections. This suggests that patients with a high
index of suspicion as brucellosis cases should be countertested for malaria and typhoid.
For effective control of brucellosis in Narok, more studies will be required to
identify the species of brucella which are prevalent in the region. The quality of water for
human consumption also needs to be assessed as typhoid was found to be a major
problem. | en |
