An epidemiological comparative study on diagnosis of rodent leptospirosis in Mazandaran Province, northern Iran / 한국역학회지

OBJECTIVES: Leptospirosis is a zoonosis caused by leptospires, in which transmission occurs through contact with contaminated biological fluids from infected animals. Rodents can act as a source of infection for humans and animals. The disease has a global distribution, mainly in humid, tropical and sub-tropical regions. The aim of this study was to compare culture assays, the microscopic agglutination test (MAT), polymerase chain reaction (PCR), and nested PCR (n-PCR), for the diagnosis of leptospirosis in rodents in Mazandaran Province, northern Iran. METHODS: One hundred fifty-one rodents were trapped alive at 10 locations, and their urine and kidney samples were collected and used for the isolation of live Leptospira. The infecting serovars were identified and the antibody titres were measured by MAT, using a panel of 20 strains of live Leptospira species as antigens. The presence of leptospiral DNA was evaluated in urine and kidney samples using PCR and n-PCR. RESULTS: No live leptospires were isolated from the kidney and urine samples of the rodents. Different detection rates of leptospirosis were observed with MAT (21.2%), PCR (11.3%), and n-PCR (3.3%). The dominant strain was Leptospira serjoehardjo (34.4%, p=0.28), although other serotypes were also found. The prevalence of positive leptospirosis tests in rodents was 15.9, 2.6, and 2.6% among Rattus norvegicus, R. rattus, and Apodemus sylvaticus, respectively. CONCLUSIONS: Leptospirosis was prevalent in rodents in Mazandaran Province, northern Iran. MAT was able to detect leptospires more frequently than culture or PCR. The kidney was a more suitable site for identifying leptospiral DNA by n-PCR than urine. Culture was not found to be an appropriate technique for clinical diagnosis.

[Seroepidemiology of cholera in Iran: a 5- year survey]

Cholera is a diarrheal disease caused by different serotypes of Vibrio cholerae. More than 200 O-antigen serotypes have been identified. Interestingly, only the O[1] and O[139] serotypes are known to cause epidemic disease. Different cases of Ogawa and Inaba serogroups have been found during last years in Iran. In this study, seroepidemiology of cholera in Iran between 2004 and 2008 was studied. In this descriptive study, fecal specimens [stool or rectal swabs] were cultured in a selective plating media like TCBS. Overnight growth of V. cholerae colony on TCBS was cultured on BHI. Colonies grown on BHI, used for biochemical and biotyping and serotyping tests. Among 93 clinical strains isolated during 5 consecutive years [2004-2008], different serogroups of V. cholerae O[1] [Ogawa, Inaba and Hikojima] biotype El Tor were identified. This study showed significantly decreasing number of Ogawa strains compared with Inaba strains in recent years in Iran. However, some rare cases of Hikojima strains have been detected in Iran in 2007 and 2008

Fatality due to shigellosis with special reference to molecular analysis vi Shigella sonnet strains isolated from the fatal cases

Shigellosis as a global human health problem is more severe than other forms of gastroenteritis and causes over a million deaths in developing countries worldwide annually. Fatality due to shigellosis is usually due to dehydration and two-third of fatalities are seen among children. The aim of current study was to describe fatal cases of shigellosis due to infection with Shigella sonnei and S.flexneri. We investigated the fatal cases of shigellosis among all children with acute diarrhea admitted to Children's Medical Center, Tehran, Iran. Bacterial isolation and identification was achieved according to standard bacteriological methods. Antibiotic susceptibility tests, plasmid profiling and ribotyping were performed to investigate the clonal relationship among the isolates. Among 1200 children with acute diarrhea, 140 [12.7%] cases had shigellosis. Of these, three patients died. No signs of severe dehydration were observed among the fatal cases. The symptoms were not improved following antibiotic therapy and all three cases died after 24 h of hospitalization despite receiving intensive treatments. Stool cultures yielded S.flexneri and S. sonnei for one and two cases, respectively. The isolates were resistant to streptomycin, ampicillin, and sulfamethoxazole-trimethoprim. 5. sonnei strains were further studied and showed a single pattern of antibiotic susceptibility and ribotyping. Mortality due to species other than 5. dysenteriae is rare, however, in current study we found S. sonnei and S.flexneri as the cause of fatality among pediatric patients during the study