Investigations of central nervous system viral infection at UHWI, 1998-1999

Preliminary results are presented for viral infections of the CNS at UHWI between July 1998 and June 1999. A total of 168 cases were referred from the following hospitals and distributed as follows: UHWI 119 (70 percent); Bustamante Children's 31 (18 percent); Spanish Town 10 (6 percent); Kingston Public 7 (4 percent); Other 2 (1 percent). Specimens received were acute and convalescent sera, throat swabs, rectal swabs and CSF. Laboratory investigations included viral culture and serology; confirmatory methods included neutralization tests, immunofluorescence (IFA) and polymerase chain reaction (PCR). The clinical diagnoses in the 168 cases included for viral CNS investigations were submitted from only 47/168 (30 percent) of cases. Viral agents were identified in 31/47 (66 percent) of the appropriate specimens received. These viruses included enteroviruses 12/31 (38 percent), human immunodeficiency virus (HIV) 9/31 (29 percent), 3/31 (9 percent) of the HIV positive patients were also positive for toxoplasmosis), dengue 6/31 (19 percent), herpes simplex virus 1/31 (3 percent), rotavirus 1/31 (3 percent), cytomegalovirus 1/31 (3 percent) and influenza 1/31 (3 percent). Enteroviruses, HIV and dengue were the viruses most frequently associated with CNS infections among the 31 cases identified. This however is not a complete representation of CNS associated with viral agents, as appropriate specimens were received from only 30 percent of the cases. This study also demonstrated a definite need for an increased understanding of appropriate specimen collection and submission necessary for the diagnosis of viral CNS infections.(AU)

Flavobacterium odoratum

A 6-week-old infant admitted to the University Hospital of the West Indies with hydrocephalus later developed ventriculities. A heavy growth of Flavobacterium odoatum susceptible to gentamicin and cefotaxime was recovered from the ventricular fluid. Since intraventricular therapy was envisaged, a pudenz reservoir was installed and ventricular fluid aspirated every 24 h to monitor treatment. Initial therapy consisted of intravenous cefotaxime, 50 mg/kg q.i.d. for 4 days. No significant reduction in the number of organisms in the ventricular fluid was achieved with this regimen. Intravenous therapy was therefore discontinued. On day 5 intraventricular therapy began with 5 mg cefotaxime 24 h for 6 days, followed by 1 mg/24 h for 4 days. Daily monitoring of intraventricular fluid indicated a high degree of antibacterial activity with rapid elimination of bacteria. Ventricular fluid remained sterile 10 days after therapy stopped. The Pudenz reservoir was removed, a ventriculoperitoneal shunt installed, and the patient discharged from hospital 4 days later without noticeable sequelae.(AU)

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)

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 investigation of an arbovirus encephalitis

A definition of an arbovirus and a broad idea of the groups and the numbers isolated and causing human infection are given. The small incidence of clinical disease compared with overall infection rates is stressed. The conditions for the successful survival of arboviruses is outlined. The investigation of the illness and origin of infection is described. The role of viral antibody in the development of encephalitis and the use of cortisone in treatment is discussed. The over-wintering of arboviruses and their capacity for latency is considered in relationship to the perpetuation of virus and the pathogenic effects on the hosts involved (Summary)

Eastern equine encephalitis virus in the West Indies and British Guiana

Investigations on Eastern Equine Encephalitis virus in the West Indies and British Guiana are reported. In Trinidad the virus was isolated from Culex mosquitoes in 1959 and 1960. In British Guiana the virus was isolated from horses in 1959 during an outbreak of Equine Encephalitis in Rupununi Savannah. Immunity to Eastern Equine virus has been demonstrated in man, birds and domestic chickens from Trinidad. (Summary)

Isolation of St. Louis encephalitis virus from the blood of a child in Trinidad, W.I

St. Louis encephalitis virus was isolated from the blood of an 11-year-old boy, resident of Trinidad, W.I., in September, 1958, in the absence of sufficient symptoms or signs to support a clinical diagnosis of encephalitis. (Summary)

Acute viral encephalitis in Jamaica

Experience with twenty-five cases of acute encephalitis believed to be of viral origin has been analyzed. There is serological evidence that three of these cases were due to St. Louis virus. An unknown virus was isolated from the serum of one patient. In most of the cases, onset of illness was sudden. Fever, headache and mental change were the main symptoms. There was a mortality rate of 16 percent. It is significant that in about 35 percent of the cases, there was some residual defect after illness. (Summary)

Arthropod-borne encephalitis viruses in the West Indies area

Sera collected from residents of Jamaica in 1956 were examined for presence of antibodies to arthropod-borne viruses by haemagglutination-inhibition, neutralization and complement-fixation tests. No evidence was found of immunity to viruses of Group A or C or to Bunyamwera virus. A large proportion of sera were positive for St. Louis or dengue virus or both. Two sera, one from a 12-year-old donor, protected against yellow fever virus (AU)

Arthropod-borne encephalitis viruses in the West Indies area Part II A serological survey of Barbados W. I

Dengue, of recent years, and yellow fever, of former years, are the only two insect-transmitted virus diseases of man for which convincing serological evidence of past or contempory presence in Barbados is demonstrated. The over-all dengue immunity rate of 30 percent is low in comparison with those of other West Indian islands (AU)

Aseptic meningitis and acute encephalitis in Trinidad, West Indies

15 cases of aseptic meningitis and 5 cases of acute encephalitis occurring during 1960 in South Trinidad are described. The cases of encephalitis began to appear at the end of the outbreak of aseptic meningitis. No casual agent could be incriminated in either outbreak and there is no evidence that these two outbreaks were aetiologically related. Aseptic meningitis was a mild illness from which recovery was usually rapid. Males outnumbered females nearly 3:1. There were no deaths. In the majority of cases the cerebrospinal fluid showed a mixed polymorh and lymphocytic pleocytosis. The mortality among the cases of acute encaphalitis was high - 3 of the 5 cases seen died. The only clinical findings of note in this group were the severe disturbance of the state of conciousness and high pyrexia. The management of such cases is a difficult problem and there is some evidence that adreno-cortical steriods may have a definite place in treatment. (AU)

Eastern equine encephalitis virus in the West Indies and British Guiana

Investigations on Eastern equine encephalitis virus in the West Indies and British Guiana are reported. In Trinidad the virus was isolated from Culex mosquitoes in 1959 and 1960. In British Guiana the virus was isolated from horses in 1959 during an outbreak of equine encephalitis in the Rupununi Savannah. Immunity to Eastern equine encephalitis virus has been demonstrated in man, birds and domestic chickens from Trinidad. (AU)

Isolation of St. Louis encephalitis virus from the blood of a child in Trinidad, W.I

St. Louis encephalitis virus was isolated from the blood of an 11-year-old boy, resident of Trinidad, W.I. in September, 1958, in the absence of sufficient symptoms or signs to support a clinical diagnosis of encephalitis. (AU)