Key Words: prevalence, brucellosis.

Brucellosis constitutes a major health and economic problem in many parts of the world, including countries of the Mediterranean Basin, the Middle East and the Arabian Gulf.1, 2. It remains an uncontrolled problem in regions of high endemicity such as the Mediterranean, Middle East, Africa, Latin America and parts of Asia.3, 4.
Humans are infected accidentally by close animal contact or consumption of animal products infected by bacteria of the genus Brucella.5 Six species are recognized, and four are well-established human pathogens. Human infection can occur through consumption of infected raw milk, raw milk products, or raw meat.6 Other means of infection include skin abrasions 7 or inhalation of airborne animal manure particles.8 Brucellosis can affect any age including children. The incidence of childhood brucellosis varies. Some authors have concluded that brucellosis in children is rare.9
Brucellosis is an endemic disease in Jordan as evidenced by a marked increase in the number of reported cases by the Jordanian Ministry of Health.10, 11
Brucellosis, especially related to Brucella abortus is not frequent in children.12 in endemic B. melitensis areas; children represent 20-25 per cent of cases.13 The present study was carried out to obtain the prevalence of childhood brucellosis among patients attending PRH for clinical profile determination.

During the period from August 1996 to September 2006, all 5726 serum samples referred to the microbiology laboratory were examined for evidence of brucellosis. All the sera were screened for B. agglutinins by slide agglutination test using B. abortus colored antigen. The positive samples (97) found with the slide method, were analysed further for the levels of antibodies by standard tube agglutination employing B. abortus-plain antigen. Of the 93 blood specimens' positive for diagnostic titres (160), blood cultures were carried out in 72 cases. The blood specimens were inoculated onto two Castaneda's biphasic media consisting of trypticase soy agar and broth. The media were incubated at 37°C with and without CO2 for 1 month. The slide agglutination test was performed using B. abortus and B. melitensis monospecific antisera.

The tube agglutination test, with the help of same antisera, was also carried out wherever it was indicated. The antisera were obtained from Murex Biotech Ltd, Dartford, England.

The synovial fluid and CSF specimens were also subjected for B. agglutinins demonstration with both slide and tube tests as mentioned above. Additional specimens such as synovial fluid, CSF, and skin were cultured using the above techniques. A detailed clinical history including epidemiological features and examination findings were recorded and analysed.

Of the 5726 serum samples studied, 93 (1.6 per cent) demonstrated B. agglutinins in diagnostic titres. The titres ranged between 160 and 5120, (Table 1). Forty-three blood specimens (59 per cent) grew B. melitensis; 42 were biotype 1 and one isolate was biotype 3. Shepherds (39 patients) were the major occupational group affected in the present study. Of the 93 patients, 58 gave a history of both animal contact and raw milk ingestion. Males (73 patients) were predominant in our study with a male to female ratio of 3:1 (Table 2). The major age group affected was 11-14 years, followed by 6-10 years (Table 2).

The youngest age recorded with brucellosis was 33 months, a female child who had a history of raw milk ingestion. The patients presented with fever, joint pain, and low backache; fever being the main presentation (Table 3). One patient had involuntary movements of limbs alone and one presented with burning feet only. Pityriasis Alba was the consistent physical finding, with fever in the majority of patients.

Hepatosplenomegaly was noticed in 48 patients, splenomegaly alone in nine, and hepatomegaly alone in five patients. Single joint involvement was found in 29 patients, the knee joint (19 patients) being the major joint affected (Table 4). Successful isolation of B. melitensis was possible in knee joint synovial fluid of three out of five patients attempted. Two joints were affected in four patients and three patients showed involvement of three joints.

Eight patients presented with complications that included papular skin lesions (3), carditis (2), chorea (1), meningitis (1), and peripheral neuritis (1) (Table 5).

The prevalence of brucellosis in the present study was 1.6 per cent (93 children), which is much higher than the reports of Spink5 and Cucullu.9

Pediatric brucellosis is uncommon where B. abortus is endemic.12 However, in areas where B. melitensis is endemic, pediatric cases are seen14-17 in endemic B. melitensis areas, children represent 20-25 per cent of the cases.13

In the present study, 93 (19.1 per cent) children out of 485 cases were diagnosed as having brucellosis during a period from 1996 to 2006. This finding is similar to the data obtained from the Middle East countries, 14-17 although lower figures have been quoted by Dalrymple-Champney 18 from England. The high prevalence of childhood brucellosis in the present series can be attributed to the endemicity of this area for B. melitensis. The isolation of only B. melitensis species supported this fact. All the 73 patients, including 32 children with brucellosis, were due to B. melitensis in Israel16 and B. melitensis remains the principal cause of human brucellosis 19

The vehicle of transmission in most of the cases in the present study was the consumption of raw milk. Like that based on the findings of our study, we conclude that the main risk factor for brucellosis is consumption of fresh, unpasteurized dairy produce.20

The studies from Saudi Arabia, 21, 22 Iran, 23 and Spain 24 report that raw milk ingestion is an important factor in disease transmission. This finding may also be the reason for our cases showing predominance in school-aged children. These children may consume raw milk while tending the flock in their spare time. Children younger than 5 years had the least infection, and this has also been reported in literature.25-28
Human brucellosis usually manifests as an acute or sub acute febrile illness, which may persist, and progress to a chronically incapacitating disease with severe complications.29 In the present study; only 15 cases (16.13 per cent) were suspected of having brucellosis, showing that the disease awareness in an endemic area is important to arrive at a clinical diagnosis like Al-Shamahy et al in which: "If clinicians are made more aware of the presenting features of brucellosis and that it should come into the differential diagnosis of fever associated with enlarged liver, spleen and lymph nodes, it will lead to an increasing index of suspicion for this infection".30
In the present series, 78 cases (83.87 per cent) on admission were classified as enteric fever, malaria, pyrexia of unknown origin, and rheumatoid arthritis, showing the protean manifestations of brucellosis and necessitating collaboration between clinician and microbiologist even in endemic areas for the diagnosis of brucellosis. So: Brucellosis should be suspected and investigated for, in any case of pyrexia of unknown origin.31

The main clinical presentation of brucellosis in children is fever, but the skeletal manifestations of the disease are also significant.23 Fever was the commonest complaint in the present study and it is worth mentioning the joint pain, which was the only complaint in 19 patients. Fever and pityriasis Alba were a common association in the present series as ; In a prospective study in Jordan, fever (88%) was the most common clinical feature encountered, followed by sweating, arthralgia and general weakness. 32 and as that in Japan in which: Fever, arthritis or arthralgia, hepatomegaly and splenomegaly were the main findings.33

Monoarticular arthritis of the knee is the most frequent reported form, 14, 15, 34 which was observed in 19 patients in the present series.

Skin lesions are an uncommon feature of brucellosis.5, 35-38 All three patients with skin lesions in the present series had papules. To our knowledge, ours is the fourth report of bacteriologically confirmed skin lesions in brucellosis in the world. The skin lesions disappeared within 8-10 days of the start of antibiotic therapy. Neurological manifestations of brucellar origin although reported, have not documented chorea as a symptom in the world literature. One patient had brucellar chorea that was successfully treated. Brucellar meningitis reported in the present series received successful treatment. Relapse was not recorded in any of the cases. In our experience combination therapy with a minimum of two drugs and extending treatment for at least 6 weeks with two drugs seems warranted to improve outcome and prevent relapses like in Henk et al: The standard treatment of uncomplicated cases in adults and children 8 years of age and older is 100 mg doxycycline twice a day for 6 weeks plus 1 g. streptomycin daily for 2 to 3 weeks. Instead of streptomycin, rifampicin may be given in combination with doxycycline (200 mg/day orally for 6 weeks) at a dose of 600-900 mg for 6 weeks.39 In our series, pediatric brucellosis is quite common since this area is endemic to B. melitensis where a strong clinical suspicion or laboratory routine screening has to be done to diagnose and institute specific therapy. Similar to Issa H et al 1n 1999 in south of Jordan "Brucella agglutination test and titer in association with a suggestive clinical picture was more sensitive than blood culture in the diagnosis of brucellosis".40