Molecular evidence for the origin of the widespread Venezuelan equine encephalitis epizootic of 1969 to 1972

Venezuelan equine encephalitis (VEE) is a mosquito-borne pathogen that has caused encephalitis in equine species and humans during sporadic outbreaks in the western hemisphere. The last, and most widespread, VEE outbreak occurred in South America, Central America, Mexico and the U.S.A. (Texas) during 1969 to 1972. We have cloned and sequenced the genome of a virulent VEE subtype I-AB virus, strain 71-180, isolated in Texas in 1971. Thirty four nucleotide differences were detected between the genome of 71-80 virus and that of subtype I-AB Trinidad donkey (TRD) virus isolated during the 1943 VEE epizootic in Trinidad. Fifteen nucleotide changes occurred in the non-structural genes, 16 in the structural genes and three in the 3' non-coding region. Only six of the nucleotide diferences resulted in amino acid substitutions: one change in each of non-structural proteins nsP1 and nsP3, two in the E2 envelope glycoprotein, one in the 6K popypeptide and one in the E1 envelope glycoprotein. The close genetic relationship between 71-180 virus and TRD virus, commonly used for production of formalin-inactivated VEE vaccines, suggests that incompletely inactivated virulent vaccine virus may have been the source of this and other VEE outbreaks. Use of formalized virulent virus was discontinued during the 1969 to 1972 panzootic. No VEE epizootics have been reported since the introduction of the live attenuated TC-83 vaccine virus (AU)

Thyroid function in dengue fever, meningitis, encephalitis, poliomyelitis and other febrile conditions

Thyroid function was studied by estimating serum thyroxine (T4), triodothyronine (T3) and thyrotropin (TSH) in 52 patients suffering from dengue fever, bacterial meningitis, viral encephalitis, paralytic poliomyelitis and other febrile illnesses. Mean serum concentrations of total T4 and T3 were significantly lower in all patients except those suffering from poliomyelitis. Serum TSH was significantly low in dengue fever and pyrexia of unknown origin (PUO). Though the TSH levels were also low in patients with bacterial meningitis and encephalitis, the differences were not statistically significant. Decreases in serum T4, T3 and FT1 in severe illnesses as compared to normal subjects may signify a state of secondary hypothyroidism of a functional type. It will be erroneous to say that decreases in T4 and T3 in systemic illnesses is entirely an adaptive or protective process to maintain metabolic rate. The possible value of thyroid hormone replacement therapy in these illnesses needs further investigations. (AU)

Dengue fever in Jamaica with shock and hypocomplementaemia, haemorrhagic, visceral and neurological complications

Ten patients with severe dengue syndrome have been seen in the recent epidemic in Kingston, Jamaica. Two patients had dengue shock syndrome. One had abnormal coagulation indices and another had severe haemorrhagic diarrhoea. Five patients had neurological syndromes of whom 3 had encephalitis, one had a meningoencephalomyelitis and one had a post-infective type demyelination syndrome. Hepatitis occurred in 2 patients, one of whom had dengue haemorrhagic fever. Pancreatitis occurred in 2 patients, one of whom had haemorrhagic fever. Concentrations of several components of serum complement were reduced only in patients with dengue shock syndrome and not in those with other complications. Although altered dengue syndromes have occurred aginst a background of multiple dengue virus types, the incidence is much lower than occurs in South-East Asia, no definite fatalities have been confirmed and adults seem to have been primarily affected rather than children (AU)