Ofukwu, A.R; Yohanna, C.A*; 1Abuh. H.A

Department of Veterinary Public Health and Preventive Medicine

University of Agriculture, Makurdi, Nigeria


1Department of Veterinary Physiology,

Pharmacology and Biochemistry

University of Agriculture, Makurdi.



A total of 1040 Serum samples obtained from human patients with acute febrile, illness at the Federal Medical Centre in Makurdi Nigeria over a period of 12 months were tested for Brucella antibodies. The test was conducted from March 2003 to February 2004. The Rose Bengal Plate Test (RBPT) and Serum Agglutination Test (SAT) techniques as described by Morgan et al (1978) and Alton et al, (1975) respectively were used. An overall prevalence rate of 7.6% (on RBPT) was obtained for Brucella infection. Most of the infections (77.2%) were caused by Brucella abortus while the rest (22.8%0) were by Brucella mellitensis. There was no association between sex or age of patients and the infection. Abattoir Workers, butchers, livestock and livestock product handlers were more affected (P<0.05) than patients in other occupations. A coordinated eradication programme, including routine test of patients and public education is recommended.


Keywords: Brucella, Infection, Hospital, Makurdi, Nigeria.



Brucellosis in humans is hardly diagnosed in hospitals in Nigeria despite suggestions that the magnitude of infections may be greater than appreciated (Njoku 1995, Rajis et al, 2003).The case of Benue State is worst as there is no known report of brucellosis in hospital patients in the entire area. This absence may be due to other diseases with similar clinical signs that are endemic and hence often diagnosed. Such diseases are, typhoid fever, malaria, and pasteurellosis with signs which include, acute recurring fever, chill, headache, fatigue, night sweat and anorexia (Rajis et al; 2003).

This similarity of signs has often led to under diagnosis or misdiagnosis of brucellosis in humans. The disease left unnoticed, had led to Malaise, orchitis, infertility, stillbirth, abortion etc with their consequent socio-economic implications. The aim of this study therefore, was to determine the presence and prevalence of Brucella abortus and Brucella melitensis antibodies in sera of hospital patients with acute febrile illness in Makurdi. It was also to highlight the consequences and suggest ways for control.



Study Area

Makurdi the capital city of Benue State is within the Southern Guinea Savannah, on Latitude 7041' North and longitude 8037' East. The Indigenous populations are mostly farmers involved in both crop and Livestock production. The livestock, especially sheep, goats and cattle are usually reared by free range. The animals only return home in the evenings to be tethered or herded into huts co-habited by humans.

Meat and fresh unpasteurised, milk "nono" from these animals are relished by the indigenous tribes. The International cattle market recently established in the town by the Federal Government of Nigeria has increased the volume of livestock trade traffic, livestock and livestock products handling and the resultant potentials for human infections.



The laboratory facilities at the Federal Medical Centre (a tertiary referral hospital) at Makurdi, and National Veterinary Research Institute (NVRI) Vom, Nigeria were used. Brucella abortus and Brucella melitensis antigens for Rose Bengal Plate Test (RBPT) and Serum Agglutination Test (SAT) obtained from the Veterinary Laboratory Agency, Weybridge United Kingdom via NVRI were used.



Sample collection

Blood samples were collected from 10 patients with febrile illness in each visit by systematic random selection (1 in every 6 patients). The visits were two times a week for 52 weeks (12 months) from March 2003 to February 2004. For a visit, 4ml of blood from each patient was collected in sterile screw capped sample bottles and processed into serum in the Laboratory as described by Alton et al (1975). Demographic characteristic of each patient was noted as the sample was being collected. A total of 1040 patient blood samples were collected and processed to sera.


Serological test

Each serum sample was screened for Brucella abortus and Brucella melitensis antibodies using the RBPT and SAT techniques as described by Morgan, et al, (1978), and Alton et al; (1975) respectively. The agglutination reactions were recorded as positive (+) or negative (-) depending on whether there were agglutinations or not. Samples with three fold litre (1:40) and above were confirmed positive for Brucella infection.

The confidentiality of the health information was maintained throughout the study, following understanding between the patients, the hospital authority and the researchers.



A total of 1040 patients made up of 614 (59%) females and 426 (41%) males were screened. Of the total screened, 79 (7.6%) were seropositive for Brucella RBPT (Table I). These positive samples consist of 63 (79.7%) and 16 (20.3%), Brucella abortus and Brucella melitensis respectively. The prevalence of Brucella abortus and Brucella melitensis among the patients were 6.1% and 1.5% respectively. Among the 63 Brucella abortus (RBPT) positive samples retested by the SAT method, 57 (90.5%) showed agglutination. The titre ranged from 1:40 (12 patients), 1:80 (29 patients) to 1:160 (16 patients) for SAT. The indicated a non significant (P<0.05) difference in sensitivity for the RBPT and SAT tests.

 Infection rates were higher in Abattoir workers/butchers (43.8%), livestock traders and breeders (33.9%) than Village Farmers (6.1%), and Civil Servants (4.1%) (Table I). Sex and age distribution of Brucella infection among the screened patients are shown in Table II and Table II respectively. Of the total 79 Brucella positive patients, 36 (45.6%) were males and 43 (54.4%) were female. There was no significant difference (P<0.05) between the sex specific prevalence rates.

Highest number of infections (33.0%) occurred in the age group of 21-40 years, with 70.9% of it occurring in the ages of 21-60 years. Age group of 0-20 years and those at 60 and above accounted for 13.9% and 15.2% of the total positive patients respectively. There was however, no significant (P<0.05) difference in the age specific prevalence rates (Table III).


The prevalence rate of 7.6% obtained in the study agrees with the findings of other workers who reported high seroprevalence of the range of 6% to 28% among hospital patients in Nigeria (Collard 1962; Falade 1978; Asanda and Agbede, 2001; Edu, 2004). The study also revealed that Brucella abortus was the main cause (77.2%) of human brucellosis, collaborating the reports from other parts of Northern Nigeria (Ocholi 1993; Asanda and Agbede 2001; Junaidu et al; 2004). The high prevalence rate and the preponderance of Brucella abortus compared to Brucella melitensis in human may be linked to its predominance in all infections in livestock, including goats in Nigeria (Falade 1974; Falade 1978; Okoyimo 2005). The low prevalence of Brucella melitensis in human infections may also be due to the fact that consumption of goat milk is low and unpopular in Benue State. This low prevalence how contrasted the report obtained among Mediterranean areas and South Africa (Junaidu et al; 2004)

The high seroprevalence of Brucella infection among occupational-risk population, with prevalence rate of up to 43.8% for abattoir workers/butchers is close to the range of 28 to 57% obtained for these group by other researchers. (Falade 1974; Ocholi 1993, Edu, 2005). Asanda and Agbede (2001) also reported that, infection seems more associated with humans engaged in livestock and livestock product activities than those engaged in other productive ventures.

The study revealed that there was no association between sex or age and human infections; even though prevalence rates in both sex and ages were high.  Similar findings were reported by Falade (1974), Junaidu et al, (2004), and Edu, (2005). It is strange that despite the high prevalence of Brucella infection of man, and it being endemic in Nigeria, it is not considered for routine laboratory referrals in cases of acute febrile illness.

A coordinated eradication programme, including public enlightenment and education should be instituted by government. Routine or regular requests for laboratory diagnosis as is being done for other endemic disease like typhoid fever and malaria should be undertaken to enhance proper diagnosis.


The authors are grateful to the Benue State Commissioner of Health and Human Services and the authorities of the Federal Medical Centre, Makurdi Nigeria for assistance in the analysis of samples.


Table I: Seroprevalence of Brucella Infection among different occupational groups of hospital patients in Makurdi, Nigeria.


Occupational Groups No. Patients Tested Brucella abortus positive Samples (RBPT) SAT positive  Brucella melitensis positive Samples (RBPT) Prevalence rate (%)
Village Farmers
Livestock Traders and Breeders
Abbatoir workers and Butchers
Civil Servants


Figures in the same column with different superscripts are significantly different (P<0.05).

Table II: Sex distribution and Sex Specific Prevalence rates of Brucella Infection among Hospital Patients in Makurdi, Nigeria.


Sex  No.  Patients Screened No. Brucella Positive patients Prevalence rate (%)
426 (41%)*
614 (59%)
1040  (100)
( ) * Sex distribution of Infected patients.

Table II: Age distribution and Age Specific Prevalence rates of Brucella Infection among Hospital Patients in Makurdi, Nigeria.


Age (years) No. Patients Screened  No. positive (RBPT) % Infection Age specific prevalence rates (%)
0 – 20
21 – 40
41 – 60
> 60  





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