Outbreak of acute hemorrhagic conjunctivitis in Maharashtra and Gujarat states of India, caused by Coxsackie virus A-24 variant.

Acute hemorrhagic conjunctivitis is associated with enteroviruses. Among these, Coxsackie A-24 variant (CA-24) and Enterovirus-70 (EV-70) are known to cause epidemics and pandemics. An outbreak of acute hemorrhagic conjunctivitis occurred in August-September 2003 in Maharashtra and Gujarat states of India. The present investigation was carried out to determine the viral etiological agent associated with the epidemic. Virus isolates were obtained from 11 eye swabs of conjunctivitis patients using HeLa/ Hep-2 cell lines. The isolates were characterized by serological and mouse pathogenecity tests, RT-PCR using enterovirus common primers (VP4-VP2), CA-24 specific primers (3C-proteinase region), EV-70 primers (VP-3) followed by sequencing, and phylogenetic analysis. The virus was characterized as a Coxsackie A-24 variant (CA-24v) and none of the isolates were found to be positive for EV-70. Sequencing of the PCR products derived from all the 11 isolates revealed 98.4% (SE 0.20) nucleotide identity within the Indian strains and 98.6% (0.50) and 94.4% (0.30) nucleotide identity respectively with the West Indies and Asian strains reported worldwide. The findings suggest that the outbreak of acute hemorrhagic conjunctivitis that occurred in Maharashtra and Gujarat states of India during August-September 2003 was caused by the Coxsackie A-24 variant (CA-24v).

Investigation of buffalopox outbreaks in Maharashtra State during 1992-1996.

During 1992-96, outbreaks of buffalopox zoonosis were reported from different villages in Jalgaon, Dhule and Beed districts of Maharashtra State. In humans, pox lesions were observed on the hands whereas in affected buffaloes and cows the lesions were noticed mainly on the teats and udder. Twenty two virus strains were isolated from the skin scabs collected from infected humans and milch animals. Neutralizing antibodies were detected not only in the sera of affected humans but also in their contacts. Detection of antibodies in young individuals from endemic area, who were neither vaccinated for smallpox nor had any contact with buffaloes or history of any poxvirus disease, is suggestive of occurrence of subclinical infection. A few children who had no contact with infected animals also showed clinical manifestations with disseminated lesions on the face, arm and buttocks, and thus suspected to have acquired infection through their infected parents or other family members indicating a possible man to man transmission. Therefore, in the light of discontinuation of smallpox vaccination, buffalopox outbreaks need to be monitored carefully as this may emerge as a serious zoonotic disease in India.

Susceptibility of laboratory-bred rodents to the experimental infection with dengue virus type 2.

Various strains of laboratory-bred rodents viz. mice [Swiss, C57BL/6, C3H/Hej, DBA/2, BALB/c, NMRI (nu/nu) and BL6 (nu/nu) and their heterozygous siblings (nu/+)], Mastomys natalensis, Wistar rat, golden hamster and Indian desert gerbil were inoculated intracerebrally (ic) with mouse-adapted dengue virus type 2 (DV-2). The inoculated animals were observed daily for dullness, anorexia, occult blood in faeces, patechial haemorrhages, lacrymation, paralysis, cachexia, death. Necropsied animals were examined for gastrointestinal haemorrhages and lymphadenopathy. The severity of clinical symptoms in various rodents declined as follows: (i) BL6 (nu/nu) mice exhibited most severe manifestation of all the aforementioned symptoms followed by (ii) NMRI (nu/nu), (iii) BL6 (nu/+) (iv) NMRI (nu/+) and C57BL6, (v) DBA, C3H/Hej and BALB/c, and (vi) Swiss. These results indicate that adaptation of DV-2 to the mouse may be an important factor in exaltation of virulence. Interstrain variation in manifestation of symptoms in mice indicates that the susceptibility to DV-2 may be determined by host genetic factors.

Nutrient composition for cultivation of Japanese encephalitis virus in vitro.

Effects of certain groups of nutrients such as glucose, essential amino acids (AA), nonessential AA, vitamins and trace nutrients on the multiplication of various strains of Japanese encephalitis virus (JEV) were studied with an aim to optimise the conditions for cultivation of the virus in porcine stable (PS) kidney cell cultures. Eagle's Minimal Essential Medium (MEM) was modified by addition of the nutrients in different concentrations and combinations. Glucose was found the most important single nutrient in promoting significantly the virus multiplication. Essential AA alone did not influence the virus yield, while in combination with glucose they caused its marked increase. Vitamins and other nutrients did not stimulate significantly virus multiplication. The study revealed that the extent of the glucose effect depends on the virus strain used.

Increased yields of Japanese encephalitis virus in heat shocked cell cultures.

Monolayers of porcine stable kidney (PS) and baby hamster kidney (BHK-21) cell lines were exposed to 43 degrees C and 41 degrees C, respectively, for 4 hrs and infected with Japanese encephalitis virus (JEV) Nakayama strain at low and high multiplicity of infection. Virus yields were increased by 0.2-2.5 log PFU/ml in heat shocked cultures compared to control cultures at 37 degrees C. This phenomenon was detected in the late phase of replication after 16 hrs post infection. The progeny virus obtained from heat shocked cultures was more thermostable.