BRUCELLOSISLobna Al juffali,Msc

Introduction

Brucellosis is a worldwide zoonosis caused by infection with the bacterial genus Brucella.

It is primarily a contagious disease of domestic

animals—goats, sheep, cows, camels and dogs.

Interhuman transmission of brucellosis has been rarely reported.

Epidemiology

Brucellosis causes more than 500,000 infections per year worldwide.

The annual number of reported cases in United States (now approximately 100 cases) has dropped significantly because of aggressive animal vaccination programs and milk pasteurization.

Most of the US cases are now due to the consumption of illegally imported unpasteurized dairy products from Mexico.

Epidemiology in Saudi Arabia

Although sporadic human cases of brucellosis were reported between 1956 and 1982 in Saudi Arabia,6 it was not until the early 1980s that the disease emerged as a major public health problem of almost epidemic Proportions.

Epidemiology in Saudi Arabia

In 1977, the incidence of brucellosisin goats in Makkah, Saudi Arabia was found

to be 0.8%, in sheep 0.5%, in camels 2.8% and in cows 3.6%.

In 1987,the incidence of brucellosis had gone up to 18.2% in goats, 12.3% in sheep, 22.6% in camels and 15.5% in cows in the Asir region.

Epidemiology in Saudi Arabia

Morbidity in humans in the Saudi population continues to be reported with increasing frequency from various regions of the country, particularly from the rural areas, and human infection is in the range of 1.6%-2.6% reported in 1999.

Causes

Ingestion of unpasteurized goat milk and related dairy products is the main route of B melitensis transmission to humans.

Slaughterhouse workers Laboratory workers (microbiologists) are

exposed by processing specimens (aerosols) without special precautions.

Microbiology

Organism Animal Reservoir Geographic Distribution

B melitensis Goats, sheep, camels Mediterranean, Asia, Latin America, parts of Africa and some southern European countries

B abortus Cows, buffalo, camels, yaks

Worldwide

B suis Pigs (biotype 1-3) South America, Southeast Asia, United States

Brucella canis Canines

The disease is caused by small, fastidious gramnegativecoccobacilli of the genus Brucella.

Clinical presentation

Fever Fever of unknown origin (FUO) is a

common initial diagnosis in patients in areas of low endemicity. It is associated with chills in almost 80% of cases.

anorexia, asthenia, fatigue, weakness, and malaise and are very common

Bone and joint symptoms include arthralgias, low back pain, spine and joint pain, and, rarely, joint swelling.

Clinical Presentation

Neuropsychiatric symptoms :Headache, depression

Neurologic symptoms of brucellosis can include weakness, dizziness, unsteadiness of gait, and urinary retention.

Symptoms associated with cranial nerve dysfunction may affect persons with chronic CNS involvement.

Clinical Presentation

Gastrointestinal symptoms, present in 50% of patients, include abdominal pain, constipation, diarrhea, and vomiting.

Cough and dyspnea Pleuritic chest pain may affect patients

with underlying empyema.

Diagnosis

Leukopenia Relative lymphocytosis Pancytopenia Slight elevation in liver enzymes is a very common

finding.

The criterion standard test for diagnosis of brucellosis is the isolation of the organism from the blood or tissues (eg, bone marrow, liver aspiration).

Culture ELISA PCR

Treatment

The goal of medical therapy in brucellosis is to control symptoms as quickly as possible to prevent complications and relapses.

Multidrug antimicrobial regimens are the mainstay of therapy because of high relapse rates reported with monotherapeutic approaches. The risk of relapse is not well understood, as resistance is not a significant issue in treating brucellosis.

The World Health Organization recommends the following for

adults and children older than 8 years:

Doxycycline 100 mg PO bid and rifampin 600-900 mg/d PO: Both drugs are to be given for 6 weeks (more convenient but probably increases the risk of relapse).

Doxycycline 100 mg PO bid for 6 weeks and streptomycin 1 g/d IM daily for 2-3 weeks. This regimen is believed to be more effective, mainly in preventing relapse. Gentamicin can be used as a substitute for streptomycin and has shown equal efficacy.

Ciprofloxacin-based regimens have shown equal efficacy to doxycycline-based regimens.

Children younger than 8 years

The use of Rifampin and Trimethoprim-sulfamethoxazole (TMP-SMX) for 6 weeks is the therapy of choice

Pregnant women:

Brucellosis treatment is a challenging problem with limited studies.

The recommendation is a regimen of Rifampin alone or in combination with TMP-SMX.

TMP-SMX use by the end of pregnancy is associated with kernicterus

Meningoencephalitis

Patients with meningoencephalitis may require doxycycline in combination with rifampin, TMP-SMX, or both.

A brief course of adjunctive corticosteroid therapy has been used to control the inflammatory process, but studies are limited.

Preventive measures

Eradication of brucellosis in animals is the key to prevention in humans. Attempts to eliminate brucellosis have been successful in many developed countries.

Public health education assumes an important role in preventing the transmission of brucellosis from animals to humans.