Chromatographic separation of herpes simplex virus

Experiments were designed to differentiate between isolates of herpes simplex virus (HSV) that are the aetiological agents of human encephalitis (neurotropic HSV) and those that were originally isolated from non-encephalitic cases (non-nueroropic HSV). Results showed that the nuerotopic HSV studied could be eluted from DEAE-cellulose columns with potassium phosphate buffer of ionic strength 0.1M or 0.15M at pH 7.0 as dertermined by mouse patogenicity and cytopathic effects. On the contrary, the eluates of the non-neurotropic HSV showed no viral patogenicity or cytopathic effects under similar conditions. Column chromatography and analysis of eluants for viral pathogenicity is a simple method for recognizing differences between neurotropic and non-neurotropic HSV. Taxonomically, this work raises the question as to whether or not HSV should be sub-classified into types designating their neuropathogenicity (AU)

Epidemiological investigation for arboviruses in Jamaica, West Indies

Arbovirus investigation in Jamaica was undertaken between 1960 and 1975. Serological studies showed that antibodies to dengue type virus and St. Louis encephalitis virus (SLE) were prevalent throughout the island for several years. In urban communities, the incidence of dengue antibody was higher than for SLE; however, in children under 10 years of age antibody to both viruses was rarely present. In rural areas, SLE was prevalent in adults and children. This virus was isolated from Culex nigripalpus (mosquitoes) and from a nestling Mockingbird, Mimus polyglottos, in the same rural area. Dengue type 3 and type 4 were isolated from the sera of patients in an urban area, during two epidemic periods, 1963 and 1968. No other group B arbovirus was encountered on the island. Group A arbovirus was virtually absent prior to the eastern equine encephalomyelitis outbreak of 1962. That virus was isolated from brain tissue of human and equines. Two strains of Cache Valley virus from mosquitoes, Anopheles grabhami, one strain from Aedes taeniorhynchus, and a strain of Wad Medani virus from a tick, Amblyomma cajenense, were also isolated (AU).

Epidemiological investigation for arboviruses in Jamaica, West Indies

Arbovirus investigation in Jamaica was undertaken between 1960 and 1975. Serological studies showed that antibodies to dengue type virus and St. Louis encephalitis virus (SLE) were prevalent throughout the island for several years. In urban communities, the incidence of dengue antibody was higher than for SLE; however, in children under 10 years of age antibody to both viruses was rarely present. In rural areas, SLE was prevalent in adults and children. This virus was isolated from Culex nigripalpus (mosquitoes) and from a nestling Mockingbird, Mimus polyglottos, in the same rural area, during two epidemic periods, 1963 and 1968. No other group B arbovirus was encountered on the island. Group A arbovirus was virtually absent prior to the eastern equine encephalomyelitis outbreak of 1962. That virus was isolated from brain tissue of humans and equines. Two strains of Cache valley virus from mosquitoes, Anopheles grabhami, one strain from Aedes taeniorhynchus, and a strain of Wad Medani virus from a tick, Amblyomma cajenense, were also isolated (AU)

Two cases of herpes simplex encephalitis at the University hospital of the West Indies

Two antigenically distinct herpes simplex viruses (HSV) are described. They were isolated from clinically diagnosed cases of acute encephalitis in a 10-year-old boy and a 36-year-old man. These viruses were identified as HSV by standard complement-fixation neutralized and cytopathology in different host systems. However, these isolates differ from classical HSV in the following aspects: (1) inability to infect adult Swis albino mice; (2) stability to organic solvents; (3) inability to be neutralized by hyperimmune sera to HSV-1; (4) requirement of chromatography on DEAE-cellulose to render them susceptible to DNase. In contrast, freezing and thawing alone were sufficient to render the HSV-1 susceptible to DNase. Further investigations will be necessary to determine whether the differences observed between the HSV-1 and the neurotropic strains provide sufficient basis for the establishment of a new sub-group for the encephalitic strains (AU)

Comparison of two human pathogenic strains with a commensal strain of Herpes Simplex virus isolated at the University Hospital of the West Indies

Comparision has been made between two human "neuropathogenic" and one "commensal" strains of herpes simplex virus. These terms are assigned to these viruses on the basis of their origin. The first two were related from patients with encephalitis and the third from a benign recurrent lesion. A number of physiochemical characteristics of these three strains were studied. The major differences observed between the "pathogens" and the "commensal" virus are: 1. The ability of the commensal herpes virus to infect adult mice while the pathogenic herpes could not. 2. The commensal herpes virus could not be neutralized by the hyperimmune sera of the pathogenic herpes and vice versa, although all crossreacted in complement fixation tests. 3. The commensal virus was significantly inactivated by chloroform, while the pathogens were not significantly affected under the same conditions. 4. Freezing and thawing followed by differential centrifugation rendered the commensal herpes vulnerable to inactivation of DNAse. Inactivation of the pathogens by this enzyme could only be acheived after chromatography on the anion exchanger, Diethyl aminoethyl. 5. The absorbtion spectrum gave a maximum peak at wave lenghts between 260-270 mu for the pathogenic virus. The peak absorption of the commensal herpes was at 280 mu. The peak at 260-270 mu by the pathogens is most likely due to the presence of nucleic acid. The peak absorption of the commensal virus is similar to that given by a typical protein. The relatively high concentration of protein which accompanies the commensal virus might account for the behaviour of this virus. 6. The "pathogenic" and "commensal" strains could be distinguished with respect to susceptibility to interferon. The commensal strain being more susceptible and also more effective in inducing interferon synthesis. 7. The method of comparision used in this investigation, and the results which reflect the marked difference between the strains of herpes simplex studied here produce some methods which may be used for differentiating between pathogenic and commensal strains of herpes simplex virus. It would appear that the methods used here are valuable to the study of viral genetics and the physiochemical study of herpes viruses. Evidence has been presented to show that there is molecular structural difference between the pathogenic and the commensal strains of herpes simplex virus. Such a difference or such differences may provide tools to probe into the pathogenic physiology of infected cells, or help to elucidate the factors responsible for neurotropicity and commensalism in herpes virus. The author is convinced that the differences cited above are genetically based. However, until further investigations are carried out, it is a subjective choice whether to consider the differences as sufficient basis for the subgrouping of herpes simplex virus. No claim is made that the distinction cited are attributes of other strains associated with encephalitis or limited lesions of recurrent herpes (AU)

The role of chickens in the epidemiology of eastern equine encephalomyelitis virus in Jamaica

Since 1962, when Jamaica experienced its first and only outbreak of eastern equine encephalomyelitis (EEE), surveillance for the causitive virus has been in progress. Wild birds, rodents, mosquitoes, sandflies and sentinels (domestic chickens, guinea pigs, mice and hamsters) have been constantly examined for EEE virus and serological conversion. In essence, only negative results have been obtained. Since June 1976, domestic chickens have been investigated as a possible reservoir and several have been found to have haemagglutinating antibodies, with titres ranging from 1:10 to 1:160. These titres fell rapidly, eg, from 1:160 to 1:10 within 60 days. These results incriminate the domestic fowl as a major reservoir for the virus, and suggest that the life of immunoglobulins against EEE is short in birds. Thus, the large number of negative serological tests found in previous investigations might be misleading since positive sera might have been missed between intervals of capture and recapture of the birds. The results indicate that investigators could usefully modify their procedure by bleeding wild birds as early as one to two weeks after initial capture. The importance and duration of the dominant avian anti-EEE virus immunoglobins should be investigated (AU).

An epidemic of dengue-like illness in Jamaica - 1963

In June 1963 an outbreak of a dengue-like illness occurred in Jamaica. The only recorded dengue epidemic in Jamaica before that of 1963 had been in 1824, as mentioned in church records of causes of death. Over 450 primary inoculations of serum from acutely ill patients and from mosquitoes associated with them were made in animals and in tissue-cell cultures. A possible isolation was made in one cell culture inoculated with material from Aedes aegypti mosquitoes, as evidenced by interference studies. Otherwise, no isolation was made, although inoculated suckling mice gave signs of disease of the central nervous system. The characterization of the epidemic as "dengue-like" was based upon the clinical course of patients and upon serological findings. (Summary)

The isolation of Cache Valley virus from mosquitoes in Jamaica

Cache valley virus has been isolated from mosquitoes on three occasions in Jamaica. Although antibodies to this virus have been encountered in man and animals, the virus has not yet been associated with clinical cases (AU)

Arbovirus surveillance in Jamaica

Following the outbreak of Eastern Equine Encephalomyelitis in Jamaica in the latter part of 1962, a surveillance was set up involving mosquitoes, birds, rodents and equines. About 650 birds have been collected to date. Sera from these were tested against EEE, St. Louis and Cache Valley viruses. Many inoculations were made for virus isolation. Serological results: 10 positive to EEE, 22 positive to SLE, and 15 positive to Cache Valley (12 wild birds and 3 chickens). Three viruses were isolated. From August 1963 - July 1964, 511 pools of mosquitoes were inoculated resulting in the isolation of 3 viruses. These are not yet identified. During the past year 223 equine sera were tested for EEE antibodies, 23 of these were positive. One hundred and sixty-six rodents were collected; organs and sera were inoculated for virus isolation and sera tested against Cache Valley, SLE and EEE viruses. There were seven positives for Cache Valley virus, 1 for EEE and 5 for St. Louis virus. No virus isolation has been made. Since June 1964, a bird banding programme has been set up in the parishes of St. Thomas and Portland. The chief objective of this programme is to determine the infiltration of the EEE and other viruses by migrant North American birds into the island. Birds are netted bled and released. These are recaptured and re-bled. Sera are inoculated for virus isolation and tested serologically for EEE antibodies. To date, 15 paired sera have been collected (AU)