Monoclonal antibody mapping of the envelope glycoprotein of the dengue 2 virus, Jamaica

Although dengue (DEN) virus is the etiologic agent of dengue fever, the most prevalent vector-borne viral disease in the world, precise information on the antigenic structure of the dengue virion is limited. We have prepared a set of murine monoclonal antibodies (Mabs) specific for the envelope (E) glycoprotein of DEN 2 virus and used these antibodies in a comprehensive biological and biochemical analysis to identify 16 epitopes. Following domain nomenclature developed for the related flavivirus, tick-bourne encephalitis, three functional domains were identified. Five epitopes associated with domain A were arranged in three spatially independently regions. These A-domain epitopes were destroyed by reduction, and antibodies reactive with these epitopes were able to block virus hemagglutination, neutralize virus infectivity, and block virus haemagglutination, neutralize virus infectivity, and block virus-mediated cell membrane fusion. Domain-A epitopes were present on the full-length E glycoprotein, a 45-kDa tryptic peptide representing its first 400 amino acids (aa) and a 22-kDA tryptic peptide representing at least aa 1-120. Four epitopes mapped into domain B, as determined by their partial resistance to reduction and the localization of these epitopes on a 9-kDa tryptic or chymotryptic peptide fragment (aa 300-400). One domain-B-reactive MAb was also capable of binding to a DEN 2 synthetic peptide corresponding to aa 333-351 of the E glycoprotein, confirming the location of this domain. Domain-B epitopes elicited MAbs that were potent neutralizers of virus infectivity and blocked hemagglutination, but they did not block virus-mediated cell-membrane fusion. Domains A and B were spatially associated. As with tick-bourne encephalitis virus, determination of domain C was more problematic: however, at least four epitopes and biochemical characteristics consistent with C-domain epitopes(AU)

Voorlopig onderzoek naar de prevalentie van rubella anti-lichamen bij vrouwen in Suriname / Interim research into the prevalence of rubella antibodies in Surinamese women

Using the haemagglutination inhibition (HAI) test, a research was carried out since 1978 in Suriname. The sera of Surinamese women in their reproductive age were tested to determine their risk for infection with the rubella virus. In various hospitals in Paramaribo, serum samples of 335 pregnant women were obtained by venapunction (5 ml. blood). To demonstrate the antibodies against rubella, the HAI test was carried out in a microtiter system, and a positive percentage of 50.4 per cent was shown. In this research, the correlation of positive cases between age, race and number of children was determined. There appeared to be no statistically significant differences. In order to obtain more data, it is recommended to extend this research

Serological evidence of infection of tacaribe virus and arboviruses in Trinidadian bats

Sera from 39 species of bats collected in Trinidad between 1972 and 1974 were tested against some or all of 18 arboviruses in hemagglutination inhibition (HI) and/or suckling mouse neutralization (N) tests. A few sera were HI-positive with Mucambo, eastern equine encephalitis (EEE), Oriboca, Restan, Manzanilla, Guama, Bimiti, and Catu. No sera were HI-positive with Mayaro, Caraparu or Maguari. Many sera inhibited one or more of the group B hemagglutinins: Ilheus, St. Louis encephalitis (SLE), dengue 2, and yellow fever (YF), positives occurred in nearly every species of bat, being most frequent with Ilheus. In N tests, a few or single sera were found to protect against Ilheus, Nepuyo, Guama, Bimiti, and Cocal, while none protected against EEE, SLE, YF or Catu. Many sera positive in HI test with Ilheus, SLE or YF failed to neutralize the respective virus. Tacaribe neutralizing antibody was demonstrated in Artibeus jamaicensis and A.lituratus, the sources of past virus isolation, in the fruit bats Sturnira lilium and Vampyrops helleri, and in the vampire bat Desmodus rotundus. Sera from 19 other species gave either negative or inconclusive results. No convincing evidence of Tacaribe antibody was found in 29 human sera, 20 from bat collectors (AU)

First isolation of Catu virus from a human in Trinidad

The first isolation of Catu virus from a human in Trinidad is reported. It is also the first human isolate outside of Brazil. A convalescent serum neutralized 5.0 logs of the homologous virus.(AU)

Studies of Patois group arboviruses in Mexico, Guatemala, Honduras, and British Honduras

Patois, Zegla, and Shark River-like arboviruses in the Patois group were isolaed in Mexico, Guatemala, Honduras, and British Honduras during 1963 to 1968. Twenty-three Patois viruses came from mosquitoes, sentinel hamsters, and suckling mice, 21 Zegla viruses from sentinel hamsters and mice and from a wild cotton rat, and two Shark River-like viruses from sentinel hamsters. Hemagglutination-inhibition(HI) and neutralizing antibody tests with Patois virus were positive with human sera from each country, and HI antibody tests were positive with sera from pigs in Mexico, Guatemala, and British Honduras and from small wild mammals, wild birds, and cattle in Mexico.(AU)

First isolation of a South American strain of eastern equine virus from a case of encephalitis in Trinidad

A South American strain of Eastern Equine virus was isolated from a fatal human case of encephalitis for the first time in Trinidad in 1970. This virus was recovered from the blood and brain of the patient. Validity of the isolate was confirmed by reisolation of the virus from the original materials. The etiological relationship of the virus to patient's illness was established by the demonstration of a secroconversion to the isolate and to the TRVL prototype strain of Eastern Equine virus. A second case of human encephalitis occurred a week later in the same geogrphical area. No virus was isolated but the diagnosis was made on the basis of an immunoconversion. (Summary)

Trials with a live attenuated rubella virus vaccine, Cendehill strain

This report summarizes closed, family, and open studies conducted sequentially over a 10 month period with the Cendehill rubella virus vaccine in more than 16,000 children and adolescents. This strain of rubella was attenuated by serial propogation on primary rabbit kidney cell cultures. Inoculation of the Cendehill vaccine produced seroconversion in 97 percent of the 3589 susceptible (seronegative) vaccinated persons. There was no spread of the virus to susceptible controls living in close contact with those vaccinated. The vaccine was well tolerated. No arthritis or arthralgia occured in 860 female subjects 13-18 years of age who were included in the study. The Cendehill vaccine would appear to meet the requirements of an acceptable vaccine (Summary)

Recovery of dengue-2 and dengue-3 viruses from man in Jamaica

Dengue-like illness has been reported in Jamaica since 1824, although the viruses concerned were never isolated. The emphasis of this work was isolating and typing the etiologic agents involved; 679 cases were reported to the Microbiology Department, University of the West Indies, during 1968 and 1969. Primary serum samples were tested; 112 of 175 indicated recent arbovirus group B infections. Primary infections and reinfections with dengue viruses were indicated by hemagglutination-inhibition and complement-fixation tests. Challenge-virus resistance technique was used to isolate eight agents from human serum. Six of these strains have been typed as dengue-3 and two as dengue-2 viruses.(AU)

Serologic responses of children after primary vaccination and revaccination against smallpox

Three serologic test methods were used to study immunologic responses of 36 children vaccinated against smallpox. Following successful primary vaccination, 97 percent of the children converted for neutralizing and HI antibodies and 18 percent for CF antibodies, 3 of 33 children had a 4-fold or greater decrease for neutralizing antibodies, but 29 of 33 children had a decrease for HI antibodies. All children became negative for CF antibodies. After the second vaccination 15 months later in which only one child failed to respond clinically, 78 percent of the children had a 4-fold or greater neutralizing antibody rise; in contrast only 18 per cent showed a significant HI antibody titer increase; 44 per cent converted for CF antibodies. (AU)

Equine encephalitis in coastal and hinterland areas of Guyana

Five hundred and eighty-six human sera collected from six coastal and hinterland areas of Guyana, including the principal enzootic foci, have been tested by haemagglutination inhibition against EEE, and WEE antigens. Sixty-eight, (11.6 percent) gave positive results with EEE; one hundred and forty-one (24 percent) against WEE. There was evidence of dual infection in 48 cases (8.2 percent). The highest titer in the case of both EEE and WEE was 1:80 and the lowest 1:10. The results of this serological survey confirm the fact that in Guyana, natural trans of both EEE and WEE arboviruses from equines to Man, has taken place. The vector is as yet unidentified as in the reservoir of virus which must presumably exist during inter-epizootic periods. (AU)

Dengue type 3 virus isolated from an Antiguan patient during the 1963-64 Caribbean epidemic

A strain of dengue type 3 virus was isolated from the blood of an Antiguan patient in cell cultures of African green-monkey kidney during studies on a dengue outbreak that occured in the Caribbean region in 1963 and 1964. The virus was adapted to mice by blind intracerebral passage. Illness appeared in mice at the 11th mouse-brain passage. Four other agents, presumed to be dengue type 3 strains, were isolated from Antiguan patients. Serologic studies on serum from patients of five Caribbean territories showed that the outbreak was due to a group B arbovirus. (AU)

Rubella immunity in Trinidad

Prevalence of rubella immunity was assayed by hemagglutination inhibition. Overall immunity, 25.5 percent, and immunity of females of child bearing age, 40.8 percent, were significantly lower than in continental areas. Urban immunity was significantly lower than in continantal areas. Urban immunity was significatly higher than rural but no significant sex or ethnic differences were noted. Geometric mean hemagglutination inhibition titers among the immune did not significantly change with age. (AU)

A comparitive study of virulences, plaque morphologies and antigenic characteristics of Venezuelan encephalitis virus strains

Virulences of VE virus strains from tropical regions of the North and South American continents were studied in adult Syrian hamsters, Swiss albino mice and cotton rats. Virulence profiles were based on frequency and time of illness and death following subcutaneous inoculation of small doses of virus as collected in nature or after only a few passages in laboratory hosts. Forty-one strains from Mexico, USA-Florida, Panama, Colombia, and Venezuela uniformity killed hamsters inoculated s.c. with 4-1000 PFU; incubation periods were usually 3-6 days, but some Panamanian and USA-Florida strains had incubation periods 1-2 days longer than strains from other countries. All of 37 strains from these countries regularly produced illness in adult mice, but killed only 71-82 percent; in adult cotton rats, signs of illness were not recognized, but death occurred in 18-30 percent. Variations in virulence profiles for mice and cotton rats among 28 Mexican strains were ogten as great as those seen among 9 strains from USA-Florida, Panama, Colombia and Venezuela. Virus strains from the Bush Bush areas of Trinidad, however, had distinctive virulence profiles. All 5 of these strains killed hamsters only after prolonged incubation periods of more than 5 days, and killed only 1 of 25 mice; neither of two strains killed cotton rats. Young and Johnson reported (Amer. J. Epid., 1969, 89 286-307) that these Trinidad strains should antigenically be classified as Mucambo rather than VE virus. The TC 83 attenuated strain of VE virus in a dose of 500 PFU given s.c. killed no hamsters, mice or cotton rats, but in some experiments employing larger doses, up to 20 percent hamsters became ill and 5-10 percent died without apparent relationship to dose. Plaque sizes and morophologies of 19 VE and 5 Trinidad Mucambo virus strains in primary chicken embryonic cell cultures did not correlate with virulence for hamsters, mice, cotton rats or man, nor with geographic, host or tissue source or year of collection. In sera of cotton rats and mice 3-4 weeks after s.c. inoculation, titers of VE virus HI antibody measured with hemagglutinin from a Mexican virus strain were similar for strains from Mexico, Colombia and Venezuela. However they were lower with USA-Florida and TC 83 virus strains and with Trinidad Mucambo virus strains, suggesting that these viruses differ antigenically from Mexican, Colombian and Venezuelan strains. Nevertheless the attenuated TC 83 vaccine virus protected adult mice against s.c. challenge by 28 Mexican and 8 other VE virus strains from USA-Florida, Panama, Colombia and Venezuela, suggesting that immunologically distinct types of VE virus based on cross-protection do not exist in these countries. (AU)

Virological investigations during the 1966 epidemic of influenza in Trinidad

Virological investigations of an influenza epidemic in Trinidad, W>I>, during the year 1966 are presented. Four strains of influenza A (Asian) virus were isolated in tissue culture and eighteen cases were diagnosed by serological methods (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)

Subclinical maternal rubella and congenital deafness

At present 40 percent of congenital deafness is inexplicable. The effect of rubella on the frequency of congenital deafness was studied five years after an epidemic of rubella in an island population. Of 87 congenitally deaf children born in 1961, the year after the epidemic, 86 had deafness as the only demonstrable congenital abnormality. Only 20 gave a history of first-trimester rubella. By modern classification the remaining 67 cases should be labelled as idiopathic congenital deafness having been ruled out. Serologic tests for rubella antibodies on 30 of the idiopathic deaf children were positive in 74 per cent, as compared to 30 per cent in a control group born within the same year. This study suggests asymptomatic rubella infection in the first trimester as an etiologic factor in congenital deafness. (AU)

Arbovirus studies in Bush Bush Forest, Trinidad, W.I., September 1959-December 1964. VI. Rodent-associated viruses (VEE and agents of groups C and Guama): isolations and further studies

Details are given on isolations of seven virus types from material collected in Bush Bush Forest during the study period: 262 of Venezuelan equine encephalitis (VEE), 71 of Caraparu-like, three of Oriboca, two of Restan, 63 of Bimiti, 56 of Catu, and 87 of Guama. Data from experimental-infection studies are presented, as well as results of serologic studies with hemagglutinating antigens of VEE and Caraparu-like viruses and some 1,200 sera of Bush Bush rodents. It was found that the natural transmission cycles of five of these virus types in Bush Bush are similar and include a period of multiplication and viremia in forest-floor rodents and a period of multiplication in mosquitoes among which Culex (Melanoconion) protesi, at least, is capable of subsequent transmission. Similar cycles are inferred for the remaining two virus types, Oriboca and Restan. In 1964 a severe reduction of the rodent population took place, Culex portesi continued abundant, and only Bimiti of the seven virus types was isolated. It is concluded that an alternate host population of sufficient size was not then available to these viruses in Bush Bush. Very little evidence was found to implicate mosquito species other than C.portesi as essential vectors during epizootic or inter-epizootic periods. (AU)

Respiratory viruses in Jamaica: a virologic and seriologic study. 3. Hemagglutination-inhibiting antibodies to type B and C influenza viruses in the sera of Jamaicans

The results presented in this paper described a survey for hemagglutination-inhibiting antibodies to one type C and 2 type B influenza viruses in Jamaica sera. Antibodies to all 3 strains were found to be very common and the distribution by age of influenza B antibodies indicates that infections by the type B viruses occur in Jamaica primarily in the 5-to 9-year and 10- to 14 year age groups. A fairly widespread immunity to influenza B infection is evident in early adult life. The incidence and titer levels of hemagglutination-inhibiting antibodies to type C influenza virus increase throughout life. Primary infections is acquired during childhood and the increasing antibody titer levels with age suggest that reinfections are not uncommon. (AU)

Respiratory viruses in Jamaica: a virological and serological study. 2. Hemagglutination-inhibiting antibodies to influenza A viruses in the sera of Jamaicans

The incidence and level of hemagglutination-inhibiting antibodies to 4 group A infleunza viruses in the population of Jamaica has shown that there is an approximately similar age distribution of antibodies to the different infleunza strains as has been encountered else-where. Antibody titres to A/Swine/1976/31 were highest in sera from older Jamaicans; antibodies titres to A1/Fort Manmouth/1/47 were maximal in the younger segment of the population and antibody titres to A/Puerto Rico/8/34 reached their highest levels in sera from intermediate age groups. The greatest incidences and levels of hemagluttination-inhibiting antibody in almost all age groups were observed against infleunza A2/Jamaica/2/63, a locally recovered type A2 strain.(Summary)