Diagnostic utility of an immunochromatography test for the detection of Leptospira IgM antibodies in domestic dogs

A cross-sectional study using 99 serum samples of dogs from southern Chile was conducted to determine the diagnostic utility of a rapid immunochromatography assay for the detection of Leptospira specific IgM antibodies as screening test and as a potential aid in the diagnosis of leptospirosis in animals with and without clinical suspicion of the disease. The Microscopic Agglutination Test (MAT) was used as reference assay. Anti-Leptospira antibodies were detected in 37.3% of the dogs with MAT. Using the immunochromatography test, specific IgM antibodies were found in 13.1% of sampled dogs. The sensitivity of the rapid test as screening assay was 29.7% (95% Confidence Interval=16.4-47.2) and the specificity was 96.7% (95% Confidence Interval=87.8-99.4). 40.0% of the canines with clinical suspicion of leptospirosis and 37.1% of dogs without clinical signs were serological reactors to MAT, but none of MAT reactive dogs with clinical suspicion tested positive in the rapid test. Rapid and user-friendly diagnostic procedures for canine leptospirosis such as this immunochromatography assay could be important tools to use in clinical practice, however, further studies are needed to obtain more information about their utility, considering that diagnostic tests could not have similar performances in different geographic locations, clinical and epidemiological contexts.(AU)

Brucellosis in India: a deceptive infectious disease.

Brucellosis is an important but neglected disease in India. This zoonotic disease is present in all livestock systems and increased demand for dairy products accompanied with changing and intensified farming practices has raised the concern for increased spread and intensified transmission of this infection to the human population with increased risk of disease. Brucellosis can be controlled by mass vaccination of livestock. Human brucellosis can be treated with a combination of antibiotics but is very difficult to diagnose and requires laboratory testing for confirmation. Only a few recent studies have addressed the prevalence and importance of brucellosis as a human disease problem in India. The disease may be overlooked and misdiagnosed because of the difficult diagnosis and the absence and lack of experience with laboratory testing. Alertness of medical staff is needed to recognize and diagnose the disease. Awareness of risk groups is needed to take appropriate preventive measures and to accept control measures.

Antibody response in typhoid fever in endemic Indonesia and the relevance of serology and culture to diagnosis.

Culture and serology were performed on blood and serum samples collected at or shortly after admission from 473 patients presented with suspected clinical typhoid. Clinical symptoms at first presentation including confusion, hepatomegaly, splenomegaly, abdominal pain, anemia, and gastrointestinal bleeding were non-specific as they were observed even more often in non-typhoid patients. Culture confirmed the diagnosis in 65.3% of the patients with typhoid fever as the final diagnosis. The sensitivity (58%) and specificity (98.1%) of a rapid dipstick assay for the detection of S. typhi-specific immunoglobulin M were somewhat lower than those of culture but higher than those of the Widal test. The dipstick assay thus may well be used in the serodiagnosis of typhoid in situation where culture facilities are not available. Combination of test results of dipstick and culture improved sensitivity to 82.5%. In laboratories that perform blood culture the dipstick assay may be used as a rapid screening tests to facilitate a rapid diagnosis. Sensitivity of the dipstick assay strongly increased with duration of illness and was higher for culture positive than for culture negative patients. Duration of illness, and different pathogen and host factors including dose of infection, pathogenicity and antigenicity, and prior antibiotic use are likely to influence the immune response, therefore the result of the dipstick assay. Duration of illness and presence of S. typhi in the blood are major factors that determine severity of disease.