Human brucellosis at a pig slaughterhouse.

Seventeen workers in a pig slaughterhouse with signs and symptoms compatible with brucellosis were clinically examined at the outpatient service of different health institutions and studied by serological tests during the period 2005-2011. Eleven blood cultures were taken and six Brucella suis strains were isolated, three biovar 1 and three with atypical characteristics. In order to confirm that these cases had no common source, a variable number of tandem repeat (VNTR) analyses were performed on 5 of the 6 strains whose results showed substantial heterogeneity in the genotypes, thereby demonstrating that the immediate origin was not the same. Two hundred adult pigs admitted for slaughter at the plant were sampled by convenience and tested by buffered antigen plate test (BPAT), serum agglutination test (SAT) and 2-mercapto-ethanol test (MET). Seven of 62 males (11%) and 25/138 (18%) females tested positive. The study results contribute information on risk scenarios for packing plant workers and underscore the need to improve plant workers' education on appropriate containment measures and to actively screen animals for swine brucellosis.

Monitoring infected dogs after a canine brucellosis outbreak.

Many episodes of canine brucellosis in dog kennels have been reported but recently an outbreak that involved pets and their owners has been described. The purpose of this study was to confirm that the outbreak had a common source and evaluate the evolution of 4 dogs involved in this outbreak after the measures implemented that included a survey of 41 animals from the same area. The variable number of tandem repeat (VNTR) analysis indicated that the B. canis isolated from the human clustered together with the isolates collected from the canine pups. Two dogs continued with bacteremia after the first antibiotic therapy and from one of them B. canis was also isolated from urine showing the importance of the later in the infection dissemination. In an effort to protect the public, stray dogs should be controlled and educational programs about the risk of this zoonotic disease should be implemented.

Brucella suis Biovar 1 isolated from a hepatic abscess drainage.

Positive cultures from hepatic abscess drainage are extremely rare, and in this case the infection would have remained undiagnosed if Brucella suis had not been isolated. Failure to correctly diagnose this zoonosis delays patient treatment and is dangerous, as in this case that could have been a laboratory-acquired disease. This type of infection is preventable if proper safety protocols are established and followed.

[Canine brucellosis in dogs in the city of Buenos Aires]. / Brucelosis canina en perros de la ciudad de Buenos Aires.

Canine brucellosis, caused by Brucella canis, provokes epidydimitis, testicular atrophy and sterility in male dogs, while in females the major symptom is miscarriage. Transmission to humans may be through contact with semen, urine and/or aborted fetuses of infected animals. Our study, observational and cross-sectional, focused on dogs in lower class neighborhoods and slums with a high rate of unmet basic needs (UBN) in 8 areas of the city of Buenos Aires. We studied 219 dogs: 184 females and 35 males, that tested negative to the buffered plate antigen test (BPAT), which ruled out infection with smooth species of Brucella. We detected anti-B. canis antibodies in 16 dogs (7.3%): 9 females and 7 males, relevant data since the urine of males is considered one of the vectors for the spread of the infection. Although we could run blood cultures on only 175 animals, we isolated B. canis in 3 (2 females and 1 male). Only 3 of the owners of dogs that tested positive consented to a serological diagnosis and two of them were positive. We highlight that the agar gel immunodiffusion test (IGID) proved to have low sensitivity, having detected only one of the 16 positive cases and none of the three confirmed by isolation. We conclude that in the areas studied, the detection of serologically positive dogs and the isolation of B. canis in 3 cases are indicators of the health hazard for the population exposed to it.

Brucellosis complicating chronic non-infectious disorders: diagnostic and therapeutic dilemmas.

There is little information in the literature on the clinical progress of brucellosis in patients affected by other non-infectious diseases; however, the infection can often trigger an exacerbation of existing underlying conditions in certain target organs. In this report we present four cases of brucellosis complicating previous diseases, and the difficulties in relation to their diagnosis and treatment. The study involved four patients with the following disorders: polycythaemia vera, pulmonary fibrosis, cirrhosis of the liver and arthritis of the knee. Brucellosis was diagnosed by classical serological and bacteriological methods. The strains involved could be isolated only in three of the four patients: two strains were Brucella abortus biovar 1 and one was Brucella suis biovar 1. Two patients relapsed 10 and 7 months after admission, another presented chronic brucellosis and received various therapy schemes, and one died. Since the best selection of antibiotics and the optimal duration of therapy remain unknown for patients having brucellosis complicated by previous pathologies, these remain at the discretion of the attending physician. Management of our patients was controversial in terms of the selection of antibiotics, duration of treatment and decision regarding surgery.

Brucelosis canina en perros de la ciudad de Buenos Aires / Canine brucellosis in dogs in the city of Buenos Aires

La brucelosis canina, causada por Brucella canis, provoca epididimitis, atrofia testicular y esterilidad en los perros, mientras que en las hembras el síntoma principal es el aborto. La transmisión al hombre puede ser por contacto con el semen, orina, y/o fetos abortados de animales infectados. El presente estudio de tipo observacional de corte transversal, se realizó en caninos de barrios y asentamientos con alto índice de necesidades básicas insatisfechas (NBI) en 8 áreas de la ciudad de Buenos Aires. Se estudiaron 219 perros, 184 hembras y 35 machos, que fueron negativos a la prueba de aglutinación con antígeno tamponado (BPAT), que descartó la infección con especies lisas del género Brucella. Sedetectaron anticuerpos anti-B. canis en 16 perros (7.3%), 9 hembras y 7 machos, este último dato es relevante ya que la orina de los machos es considerada uno de los medios de diseminación de la infección. Aunque sólo se pudieron tomar hemocultivos a 175 animales, en 3 (2 hembras y un macho) se aislaron B. canis. Sólo 3 de los dueños de los perros positivos accedieron al diagnóstico serológico y dos resultaron positivos. Destacamos que la prueba de inmunodifusión en gel de agar (IGDA) ha demostrado ser poco sensible, detectó sólo uno de los 16 casos positivos y ninguno de los tres confirmados por aislamiento. Concluimos que en las áreas estudiadas el hallazgo de perros serológicamente positivos y el aislamiento de B. canis en 3 casos, son indicadores del riesgo en el que se encuentra la salud de la población expuesta.

Canine brucellosis, caused by Brucella canis, provokes epidydimitis, testicular atrophy and sterility in male dogs, while in females the major symptom is miscarriage. Transmission to humans may be through contact with semen, urine and/or aborted fetuses of infected animals. Our study, observational and cross-sectional, focused on dogs in lower class neighborhoods and slums with a high rate of unmet basic needs (UBN) in 8 areas of the city of Buenos Aires. We studied 219 dogs: 184 females and 35 males, that tested negative to the buffered plate antigen test (BPAT), which ruled out infection with smooth species of Brucella. We detected anti-B. canis antibodies in 16 dogs (7.3%): 9 females and 7 males, relevant data since the urine of males is considered one of the vectors for the spread of the infection. Although we could run blood cultures on only 175 animals, we isolated B. canis in 3 (2 females and 1 male). Only 3 of the owners of dogs that tested positive consented to a serological diagnosis and two of them were positive. We highlight that the agar gel immunodiffusion test (IGID) proved to have low sensitivity, having detected only one of the 16 positive cases and none of the three confirmed by isolation. We conclude that in the areas studied, the detection of serologically positive dogs and the isolation of B. canis in 3 cases are indicators of the health hazard for the population exposed to it.

Diagnosis of human brucellosis caused by Brucella canis.

The transmission of Brucella canis to man commonly occurs through contact with infected dogs or their secretions, or through direct laboratory exposure. The disease is underdiagnosed due to a general lack of serological testing facilities and misconceptions concerning its prevalence. This report shows the potential use of an indirect ELISA (IELISA) for the diagnosis of human brucellosis caused by B. canis in a population of patients negative by smooth-Brucella antigen tests but positive by rapid slide agglutination test (RSAT). One hundred and ten sera from asymptomatic people found negative by tests using smooth Brucella abortus antigen and by RSAT showed an IELISA specificity of 100 % when a cut-off value of 27 % positivity (%P) was selected. For 17 sera from patients with positive B. canis culture or in close contact with culture-positive dogs, the IELISA sensitivity was 100 % with the same cut-off value. The positive patients presented clinical symptoms similar to brucellosis caused by other species of Brucella and some of them received antibiotic treatment and made good progress. Using this cut-off value, we studied 35 patients with negative blood cultures but positive RSATs, and IELISA detected 18 as positive; of the 17 IELISA-negative, two were RSAT-positive at dilution 1 : 2 and 15 were weakly positive with pure serum. These samples were probably from patients at an early stage of infection or indicate false-positive results. No cross-reaction was observed among the sera from nine cases with a diagnosis other than brucellosis, but cross-reactivity was evident in sera from patients infected with smooth-Brucella species. Since routine brucellosis diagnosis does not include B. canis investigation, infection with this species may be more widespread than is currently suspected. The RSAT could be a suitable screening test for the diagnosis of B. canis human brucellosis, and a supplementary technique, such as IELISA, performed on all positive RSAT samples that were negative by B. abortus antigen could ensure diagnostic specificity and confirm the diagnosis.

Unusual clinical presentation of brucellosis caused by Brucella canis.

Brucella canis is considered a rare cause of human brucellosis. The clinical importance of this infection may have been underestimated so far because of difficulties with presumptive diagnosis. The case described here presented symptoms compatible with brucellosis but the routine tests using Brucella abortus antigen were negative. The infection would have remained undiagnosed if culture had not been positive. This case illustrates the potential for a favourable outcome in Brucella canis diagnosis and supports recommendations for the use of B. canis serology. The infection should be suspected in patients with compatible symptoms and negative serology for B. abortus antigen.

Fluorescence polarization assay for diagnosis of human brucellosis.

Fluorescence polarization immunoassay (FPA) uses molecular rotational properties to measure antibody binding to antigen directly. The potential use of this method was assessed in comparison to a competitive enzyme immunoassay (CELISA) and conventional serological tests for the diagnosis of brucellosis on a total of 587 human sera. Based on 340 sera from asymptomatic blood donors with no evidence of brucellosis, the specificity of the FPA was 97.9 % using a cut-off value of 72 mP. Sera from Brucella-infected patients (11 Brucella melitensis, 32 Brucella abortus, 32 Brucella suis and one Brucella sp.) yielded a sensitivity estimate of 96.1 %. In tests on 84 sera from suspected brucellosis patients, the FPA detected 80 cases. Of 87 sera from patients with probable infection, 15 were detected by both CELISA and FPA, three by CELISA only and four by FPA only. The discrepancies in both groups involved sera with low, declining titres. The FPA uses a sample of 40 micro l serum, takes about 5 min to complete and has been demonstrated to be accurate for the detection of antibodies to B. abortus, B. melitensis and B. suis and for identifying patients suffering relapses. Because of the ease of the procedure, it could be readily adopted for use in clinical laboratories and blood banks.