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Biomedical subjects

A C Mitra

Publications and source records attributed to A C Mitra.

At least 19 recordsLinked to original sources
PubMed1976

Concurrent smallpox and chickenpox.

Three patients showing smallpox- and chickenpox-like lesions simultaneously were investigated virologically. Both infections were confirmed in the laboratory and, in one case, by electron microscopy.

Adolescent↗
PubMed1975

Clinical observations on smallpox: a study of 1233 patients admitted to the Infectious Diseases Hospital, Calcutta, during 1973.

The paper presents clinical observations on 1 233 persons with smallpox who were admitted to the Infectious Diseases Hospital, Calcutta, in 1973. The disease was of the modified type in 53 patients (4.3%), the ordinary type in 717 (58.2%), the flat type in 249 (20.2%), and the haemorrhagic type in 214 (17.3%). The fatality of these types of smallpox was found to be 5.7%, 26.8%, 88.4%, and 98.1%, respectively, and the overall case fatality was 50.7%. The haemorrhagic type was found mainly among older patients and affected males more often than females. The vaccination status of 1 218 patients was known. Of these, 901 (73.9%) were unvaccinated and had a fatality rate of 53.4%, whereas the 317 (26.1%) vaccinated patients had a fatality rate of 36.5%. Among the 201 haemorrhagic cases, 145 patients were unvaccinated (16.09% of the total number unvaccinated) and 56 (17.67%) had been vaccinated. Of 34 patients vaccinated during the incubation period, 19 (41.1%) died, whereas of 18 patients who had been vaccinated after the onset of fever, but before the appearance of rash, 9 (50%) died.

Adolescent↗
PubMed1975

The minimum protective level of antibodies in smallpox.

Blood samples from 57 contacts of 6 smallpox cases were tested for haemagglutination-inhibiting (HI) and neutralizing antibodies. All 6 contacts who subsequently developed smallpox were unvaccinated and had neutralizing antibody titres of 10 or less. However, 6 unvaccinated contacts with similar antibody levels did not develop smallpox. None of the 41 vaccinated contacts, regardless of their antibody level, contracted the disease.

Adolescent↗
PubMed1974

Virus content of smallpox scabs.

Log titres of smallpoxvirus (pock-forming units per 0.1 g of scab) were estimated in scabs from 5 patients from the 13th to the 24th days of illness. They were found to vary from 3.72 to 6.54 with no diminution as convalescence progressed, and they were not related to the primary vaccination status of the patient or the clinical severity of the disease.

Adolescent↗
PubMed1974

Pattern of intrafamilial transmission of smallpox in Calcutta, India.

The pattern of intrafamilial transmission of smallpox in Calcutta was studied in 43 index cases, 3 of which were haemorrhagic, 14 confluent, and 26 discrete. They had 741 contacts. The attack rate in vaccinated contacts was significantly less than in unvaccinated contacts, but there was no such difference in the case rates caused by severe and mild index cases. Females had higher attack rates than males, the difference being more marked among the vaccinated. The vaccination status of the index cases seemed to affect their secondary case rates. The incidence of secondary cases among contacts living in the same room as a patient and in other rooms in the same compound was practically equal.

Adolescent↗
PubMed1973

Virus excretion in smallpox. 1. Excretion in the throat, urine, and conjunctiva of patients.

Excretion of virus in the throat, urine, and conjunctiva of smallpox patients was studied daily for 2-3 weeks after the onset of fever. The virus titre in the throat and urine of haemorrhagic and confluent cases was higher than in discrete cases. The duration of virus excretion was also greater in confluent cases than in discrete cases. Conjunctival swabs from all 12 smallpox patients with conjunctivitis were positive for virus. The duration and titre of virus excretion in the throat, urine, and conjunctiva of patients were not related to their age or sex and did not depend on whether or not they had received a primary vaccination.

Adolescent↗
PubMed1973

Virus excretion in smallpox. 2. Excretion in the throats of household contacts.

Throat swabs of 34 of 328 family contacts of 52 smallpox cases, examined 4-8 days after the onset of the disease in the family, were positive for variola virus. The log titre of virus per swab ranged from 2 to 3.95. A higher proportion of unvaccinated than of vaccinated contacts excreted the virus. Only 4 of the virus-positive contacts developed clinical smallpox; this occurred 5-7 days after their swabs were examined. Excretion of virus in the throats of these contacts, a few of whom were in the incubation period of the disease, suggests the possibility that they could have spread the infection. This possibility, if kept in mind, may help in tracing the source of infection or in determining the incubation period in a few instances when difficulty is experienced.

Adolescent↗
PubMed1973

Evaluation of the precipitation-in-gel reaction in the diagnosis of smallpox.

Specimens of vesicular or pustular fluids and of scabs from patients with smallpox as well as emulsions of variola-infected chorioallantoic membrane (CAM) were tested for virus titres and by the precipitation-in-gel (PIG) reaction. They were also tested after exposing them directly to sunlight and after keeping them at temperatures of -20 degrees C, 4 degrees C, and 25 degrees C. It was found that when extracts of fresh specimens were diluted to the point where the PIG reaction became negative there was still a titre of 10(4)-10(5) infectivity in the swab extracts and 10(3)-10(4) infectivity in the scab extracts. It was also found that the PIG reactions were all negative on specimens that were kept for 14 days at 25 degrees C, and that several were negative after only 7 days; the loss in infectivity titre, however, was only slight in all the specimens tested. It is concluded that the laboratory diagnosis of smallpox by virus inoculation of CAM is more reliable than by the PIG test.

Animals↗