Coronaviruses in guano from Pteropus medius bats in Peradeniya, Sri Lanka.

Bats are a unique group of mammals well suited to be hosts for emerging viruses. With current rates of deforestation and urbanization, redistribution of bat habitats to urban and suburban areas may bring bats into closer contact with livestock and humans. Common flying fox, Pteropus medius (previously known as Pteropus giganteus), forms large communal roosts on treetops, often in close proximity to human habitation in Sri Lanka. This report describes the detection of coronavirus RNA in P. medius bat guano collected in Peradeniya, Sri Lanka. These viruses had >97% nucleotide identity with coronaviruses detected in Cynopterus sphinx, Scotophilus heathii and S. kuhlii bats in Thailand. Pteropus medius is widespread in Asia and appears to excrete group D coronaviruses, which are hitherto confined to bats; however, these findings may have public health implications in the future.

Susceptibility of New Entrant University students in Sri Lanka to varicella zoster infection.

To investigate the susceptibility of Sri Lankan new entry university students to varicella zoster virus (VZV) infection, a cross-sectional descriptive study was carried out among new entrant medical and engineering students of the University of Peradeniya, Sri Lanka. Self-reported history of chicken pox was studied first, followed by serological evaluation for VZV IgG antibodies. A total of 451 students participated in the study out of which 189 (41.9%) reported a history of chicken pox. Median age of reported age of acquiring the disease was 14 years with an interquartile range of 10 to 17 years. Only 25% of the population reported history of infection prior to age of 10 years. The seropositive rate of VZV IgG antibodies among undergraduates with a negative history of chicken pox was 10.1% ( 25/247). The present study indicates that nearly half (222/436) of the study population (50.9%, 95% CI 46.2-55.6) was susceptible to VZV infection.

Methicillin resistant Staphylococcus aureus: the scale of the problem in a Shri Lankan hospital.

A three month surveillance study of methicillin resistant Staphylococcus aureus (MRSA) was carried out in the male surgical unit of the General Hospital, Peradeniya, Shri Lanka. Nose, throat, axillary, perineal and wound swabs were taken from 251 patients and 35 staff members. Eighty-four (27.5%) of 305 isolates of S. aureus from patients were MRSA. Seventy-three of these isolates were also resistant to penicillin, tetracycline, erythromycin, gentamicin, chloramphenicol and co-trimoxazole. All isolates were sensitive to fusidic acid, clindamycin, vancomycin and rifampicin. The acquisition of MRSA was higher than of methicillin sensitive S. aureus (MRSA). No deaths occurred due to MRSA. Staff carriage was only 6%. The treatment and management of MRSA in hospitals with very poor resources requires further study of interventions which are practicable in this situation.

Ileal perforation in typhoid: bacteriological and immunological findings.

In typhoid perforation patients, Salmonella typhi was isolated from blood in 4%, ileal contents in 23%, peritoneal pus in 13% and from mesenteric lymph nodes in 71%. While isolation of S. typhi was made from patients with less than 4 days of chloramphenicol therapy, cultures were negative from these sites after 5 days of therapy; however, S. typhi appeared to remain viable in the lymph nodes even after such therapy. All isolates of S. typhi were sensitive to chloramphenicol. Significant SAT titers (0 > or = 1/240) were obtained in only 7/21 (33%) of patients. The perforated group had lower geometric mean titers (0-1/138; H-1/46), when compared to matched patients with uncomplicated typhoid fever (0-1/476; H-1/148). This difference was significant (0- p < 0.005; H- p < 0.0025). The two groups (uncomplicated and perforated) showed no significant difference in total serum IgG, IgM and IgA or isohemagglutinin levels, indicating that the apparent hyporeactivity was not due to a generalized humoral immunodeficiency. Mesenteric lymph node histology showed hyporeactivity in both the T cell and B cell zones. These findings are discussed with the suggestion that S. typhi-specific host immunological hyporeactivity could be an explanation for these observations and a basis for the pathogenesis of perforation. Aerobic cultures of the peritoneal pus gave 39 isolates from 25 patients; the predominant isolates were Escherichia coli (24) and Klebsiella pneumoniae (12). On no occasion was S. typhi the predominant isolate. Gentamicin and kanamycin were the only two antibiotics which were consistently effective in vitro against the aerobic isolates from peritoneal pus.

Chloramphenicol resistant typhoid fever.

We report a patient with typhoid fever caused by a strain of Salmonella typhi which was resistant to chloramphenicol. This is the first documentation of chloramphenicol resistant Salmonella typhi in Sri Lanka.

An evaluation of the SAT in the diagnosis of typhoid.

Salmonella typhi O and H antibody titres were determined by the Standard Agglutination Test (SAT) in 85 patients with bacteriologically proven typhoid, 102 patients with non-typhoidal febrile illnesses (control group 1), and 170 healthy subjects (control group 2). An O antibody titre of 1/120 occurred in 93% of patients with typhoid fever (7% false negatives), and in 17% and 12% control groups 1 and 2 respectively. An H antibody titre of 1/120 was found only in 64% of patients with typhoid (false negatives in 36%). At titres other than 1/120, the proportion of false negatives or false positives increased ie. the sensitivity and specificity decreased. Although the SAT continues to be used in Sri Lanka as the main diagnostic test in typhoid, the sensitivity and specificity of this test fall below the requirements of a useful diagnostic test.

Cell mediated and humoral immune responses in human typhoid fever.

The leucocyte migration inhibition test (LMIT) and the Widal test have been used to investigate the cell mediated (CMIR) and humoral immune responses (HIR) in 43 typhoid patients in comparison with the responses in 83 control subjects in two groups (65 normal persons and 18 sewerage workers) who were occupationally exposed to human faeces. The patients and the sewerage workers showed significantly higher CMIR than the normal persons. The O, H, and Vi antibody titres were significantly higher in the patients than in both control groups. Neither the CMIR nor the antibody titres differed significantly between the adult and paediatric patients. While we confirm that a CMIR does develop in typhoid patients, we found no correlation between the CMIR and the occurrence of complications. Neither the duration of the illness (after the first week) nor chloramphenicol therapy affected the CMIR or the HIR.