Molecular analysis of the cholera toxin gene & antibiotic sensitivity profile of Vibrio cholerae O1 & O139 associated with mixed infection.

In the context of the reemergence of V. cholerae O1 in India and the recent evidence that O139 strains could have evolved from O1 E1 Tor strains, restriction fragment length polymorphism (RFLP) of the rRNA and the ctx genes and the antibiotic sensitivity profile of the two strains of V. cholerae, one an O1 and the other an O139, associated with mixed infection, were examined to determine their relatedness. Our results demonstrate that although the strains belonged to different clones of V. cholerae, they showed similar antibiotic sensitivity, profile indicating some exchange of genetic elements.

Strategies for production of a potential candidate vaccine for cholera.

First attempt at cholera vaccination was made by Jaime Ferran in 1884. Since then, a variety of strategies and methods have been evolved to create a safe, efficacious vaccine against cholera. For the first few years emphasis was on the development of parenteral vaccines. However, as a result of accumulation of a tremendous amount of knowledge, not only on Vibrio cholerae-the causative agent, but also on its interaction with the host, emphasis has shifted towards the development of oral vaccines. Two such vaccines, one killed, a whole cell/B subunit combination vaccine and the other a live attenuated one, have shown promise. The combination vaccine in its present state of development confers only a transient protection in young children, while the live attenuated one produces adverse reaction. To combat these, various strategies are being evolved. In one attempt, a potential candidate vaccine strain has been constructed from a non-reactogenic clinical isolate of V. cholerae, which is devoid of all known major virulence genes and is also a good colonizer. In animal studies this construct has shown considerable promise. This review discusses the various strategies that have been employed so far in the quest for an ideal cholera vaccine.

Study of primary convergence insufficiency.

The present study was done to find out the incidence of primary insufficiency of involuntary convergence and evaluate the relative efficacy of synoptophore treatment against home exercise in its management. During the period of study, 2162 cases in the age group 15 to 35 years were studied for convergence in detail. It was found out that the incidence of primary convergence insufficiency is quite high (7.7% of total orthoptic clinic attendance). It commonly affects those who are constantly engaged in near work. Response to synoptophore exercises and home exercises is comparably equal. Recurrence of the ailment after stopping the exercises is not uncommon.