Epilepsy, cysticercosis, and toxocariasis: a population-based case-control study in rural Bolivia.

OBJECTIVE: To assess the relationship between epilepsy and infection with Taenia solium and Toxocara canis with a case-control study, in the rural area of the Cordillera Province, Bolivia. METHODS: A preliminary two-phase door-to-door prevalence survey determined the prevalence of epilepsy and identified cases and control subjects. At least two control subjects per case were selected, matching on sex, age, and community of residence. Cases and control subjects were assessed serologically for antibodies against T. canis by ELISA and against T. solium by enzyme-linked immunoelectrotransfer blot (EITB). RESULTS: The prevalence survey found 130 confirmed cases of epilepsy, of which 113 were eligible for the case-control study (59 partial seizures and 54 generalized seizures). Two hundred thirty-three control subjects were selected. Multivariable analysis for a matched case-control study was carried out. There was an association between EITB positivity for T. solium and epilepsy with an OR of 1.85 (95% CI 0.99 to 3.4) for all cases. A stronger association was found in those with partial epilepsy with a late onset of disease (15 years and older), where the OR was 3.66 (95% CI 1.10 to 12.10). A positive association was also found with T. canis for all cases with an OR of 2.70 (95% CI 1.41 to 5.19). This increased for those with late-onset partial epilepsy to an OR of 18.22 (95% CI 2.10 to 158.10). CONCLUSION: This finding suggests that both neurocysticercosis and toxocariasis may in part explain the higher prevalence of epilepsy, particularly partial epilepsy, in developing countries.

Serologic survey for antibodies to Borrelia burgdorferi in sheep, goats and dogs in Cordillera Province, Bolivia.

A serosurvey for antibodies to Borrelia burgdorferi using an enzyme-linked immunosorbent assay (ELISA) was conducted on sheep, goat and dog serum samples collected in Cordillera Province, Bolivia, in 1992 Sera from 98 sheep, 218 goats and 43 dogs were tested. The observed seroprevalence in sheep and dogs was 0.0%, whereas the seropositivity rate for goat serum samples was 5.0%. Upon analysing 10 positive sera by Western immunoblotting, five reacted against the specific protein antigens and all of them met the criteria for positivity on the basis of immunoglobulin G (IgG) bands, indicating that goats in Cordillera Province were exposed to B. burgdorferi. These findings, which are further proof of the existence of B. burgdorferi infection in Bolivia, indicate the serologic analysis of goats as a suitable tool for Lyme borreliosis surveillance.

Serological survey of leptospiral infections in sheep, goats and dogs in Cordillera province, Bolivta.

A serological survey for antibodies to Leptospira spp. was conducted on sheep, goat and dog serum samples collected in three localities in Cordillera province in the southern part of the Santa Cruz Department (Bolivia) in 1992. A total of 98 sheep, 218 goats and 43 dogs were tested against 29 leptospiral serovars using the microscopic agglutination test. At the time of blood collection all of the examined animals appeared healthy and presented no clinical sign suggestive of leptospirosis. Antibody prevalences, as determined by positive results at a 1:100 dilution or higher, was 14.3% in sheep, 19.7% in goats, and 14.0% in dogs. Agglutinins against six serovars (poi. shermani, pomona, canicola, javanica, djasiman) were found in positive animals. The highest serological prevalence in sheep and goats was recorded for serovar poi, followed by pomona in sheep and shermani in goats. Titres to shermani were the commonest in dogs. The results of this survey indicate that leptospiral infection is common in south-east Bolivia and that serovars of several serogroups concur in the etiology.

Study of neutralizing monoclonal antibodies to bovine herpes virus type-1 (Cooper strain) by immunoperoxidase and immunoelectron microscopy.

Three neutralizing monoclonal antibodies (mAbs) that are specific against bovine herpes virus Type-1 (BHV-1) were studied as to their viral specificity by immunoperoxidase and immunoelectron microscopy. Microscopic examination of GBK BHV-1 infected cells revealed peroxidase activity represented by red-brown granular deposits in the nucleus and cytoplasm. No immunoperoxidase activity was observed in negative controls. For the ultrastructural observations, two approaches were used. Firstly we tested a pre-embedding technique using GBK infected cells, mAbs and gold conjugated-protein A. Gold particles were observed linked to the viral envelopes and to the host cell membrane. Alternatively, a second technique employed BHV-1 purified by potassium tartrate gradients, mAbs and gold conjugated-protein A. After performing the immune reaction, the samples were adsorbed to formvar-coated grids, stained with phosphotungstic acid and observed in a transmission electron microscope. Gold particles were mainly attached to the virion envelope.

Prevalence of antibodies to Borrelia burgdorferi, Borrelia parkeri and Borrelia turicatae in human settlements of the Cordillera Province, Bolivia.

A seroepidemiological study to determine the prevalence of human Lyme borreliosis and tick-borne relapsing fever was carried out in three communities (Camiri, Boyuibe and Gutierrez) of the Cordillera Province, Santa Cruz Department, south-eastern Bolivia. Anti-B. burgdorferi, anti-B. turicatae and anti-B. parkeri antibodies, tested by the indirect immunofluorescent assay (IFA), were detected in 10.8, 16.1 and 8.2% of the serum samples tested, and confirmed by IFA-ABS in 1.3, 1.3 and 1.0%, respectively. This is the first report of the presence of Lyme borreliosis and tick-borne relapsing fever in Bolivia. For Lyme borreliosis these findings represent a further datum to support its existence in South America.

Characterization of foot-and-mouth disease virus by monoclonal antibodies.

Monoclonal antibodies (MAbs) were produced against foot-and-mouth disease (FMD) virus types O1 Campos Br1/58, A24 Cruzeiro Br1/55, and C3 Indaial Br1/71, which are the strains used for production of FMD vaccines in the majority of South American countries. Within the library of MAbs produced, a group was selected on the basis of their neutralizing titer in cell culture, protective titer in suckling mice, sensitivity to trypsin, and specificity for virus structural proteins. The MAbs were utilized in an ELISA test format to compare European and South American representative field isolates with vaccine production strains in their r1 relationship as obtained by 50% complement fixation (CF50) with polyclonal antibodies (PAb) and their virus neutralization (VN) relationship obtained with sera from one-time-vaccinated and from revaccinated cattle, respectively. The MAbs selected varied in their reactivity against the different strains and, therefore, enabled us to compare field FMDV strains to those against which the MAbs were produced, with definite advantages over the r1 and VN ratios. Thus, panels of MAb produced with the vaccine strains and appropriately selected are significantly useful for the FMD-control programs because they serve to provide guidance on the immunological coverage provided by the vaccines against FMDV strains circulating in the field. The MAbs are also useful for the differentiation of FMD virus strains.

Anticuerpos monoclonales específicos para herpesvirus bovino tipo-1 (cepa Cooper)

Anticuerpos monoclonales fueron preparados contra herpesvirus bovino tipo 1 (BHV-1) purificado y se seleccionaron varios de acuerdo con su habilidad de neutralizar la infectividad viral. El virus fue purificado por dos métodos alternativos de concentración, con polietilenglicol seguido de ultracentrifugación sobre un colchón de sacarosa al 25 por ciento (p/p) o usando un gradiente linear de tartrato de potasio. De un total de 204 líneas celulares que segregaban anticuerpos para el virus, obtenidas en dos fusiones, se seleccionaron y expandieron clonalmente 39 hibridomas. La selección se basó en su reactividad específica por ELISA. De éstos, 11 anticuerpos monoclonales fueron capaces de neutralizar BHV-1 total o parcialmente, con o sin el agregado de complemento. Siete anticuerpos monoclonales fueron producidos (en la forma de fluido ascítico) y purificados por precipitación en sulfato de amonio. De éstos, dos fueron capaces de prevenir la penetración de virión luego de su adherencia a la células. Asimismo, tres anticuerpos monoclonales fueron seleccionados para ser usados en las pruebas de inmunoperoxidasa para la detección del BHV-1 en cultivos celulares infectados.

Monoclonal antibodies (McAbs) were prepared against purified Bovine Herpesvirus Type-(BHV-1) and selected for their ability to neutralize viral infectivity. Viral purification was performed by polyethylene glycol concentration and ultracentrifugation on a 25% (w/w) sucrose cushion, and by potassium tartrate linear gradient. Out of 204 cell lines expressing antobodies to the virus, obtained in two fusions, 39 hybridomas were selected and cloned based on enzyme-linked immunosorbent assay (ELISA) reactivity. Eleven McAbs were able to neutralize BHV-1 partially or totally, with or without complement. Seven McAbs were produced as ascitic fluid, and ammonium sulfate-purified. Of these, two were able to prevent virion penetration into the cell after attachment. Three neutralizing McAbs were selected for use in immunoperoxidase tests for detecting BHV-1 in infected cell cultures.

Producción de anticuerpos monoclonales contra antigenos grupo especificos del virus de la lengua azul

Se desarrollaron anticuerpos monoclonales contra el antígeno grupo específico del virus de la lengua azul serotipo 4. Los hibridomas se obtuvieron a partir de células de bazo de ratones BALB/c inmunizados, fusionadas con células de mieloma Sp2/O-Ag 14, usando polietilenglicol 1500 y clonados por dilución limitante. El sobrenadante de ocho anticuerpos monoclonales se probó, por inmunodifusión en gel de agar, contra antígenos grupo específicos procedentes de cuatro laboratorios diferentes. Todos mostraron una buena reacción con el antígeno grupo específico. Por lo tanto, estos anticuerpos monoclonales tienen gran potencial para ser usados en la identificación de anticuerpos grupos específicos mediante la prueba ELISA de competición.

Monoclonal antibodies (MAbs) against the group-specific antigen of Bluetong virus were developed using Bluetong virus serotype 4. The hybridomas were abtained from immunized BALB/c spleen cells fused with myeloma cells line Sp2/O-Ag14 using polyethylenglycol 1500, and cloned by limiting dilution. The supernatant from eight MAbs was tested against group-specific antigens used in agar gel immunodiffusion tests by different laboratories. The eight monoclonal antibodies presented good reactions to the group-specific antigen. Therefore, these MAbs have great potential for application in the identification of group-specific antibodies by competitive ELISA tests.

Extensive antigenic heterogeneity of foot-and-mouth disease virus of serotype C.

The antigenic behavior of 46 field isolates of foot-and-mouth disease virus (FMDV) of serotype C has been studied with a panel of 24 monoclonal antibodies (MAbs) prepared against FMDV C1 or FMDV C3 Indaial. Reactivities were assayed by immunodot, immunoelectrotransfer blot, and neutralization of infectivity. The epitopes recognized by the 10 nonneutralizing MAbs are conserved in all isolates analyzed. In contrast, extreme antigenic heterogeneity is documented with regard to reactivity with 14 MAbs that, on this basis, define at least 12 epitopes involved in neutralization of FMDV of serotype C. The 31 isolates from South America were divided into 17 distinct antigenic groups and the 15 isolates from Europe into 7 groups. Lack of correspondence between antigenic composition and the origin--date and place of isolation--of the viruses was noted in several instances. Antigenic heterogeneity is shown among epidemiologically closely related FMDVs. In most--but not all--cases tested, a good correlation was found between binding of a neutralizing MAb to virions and its ability to neutralize infectivity. It is concluded that variation of epitopes involved in neutralization of FMDV is extensive among subtypes of serotype C and also among individual isolates of one subtype.

Rapid selection of genetic and antigenic variants of foot-and-mouth disease virus during persistence in cattle.

Rapid evolution of foot-and-mouth disease virus (FMDV) is documented during persistent infections of cattle. The carrier state was established experimentally with plaque-purified FMDV of serotype C3. Virus was recovered from the esophageal pharyngeal area of the animals up to 539 days postinfection. Analysis of capsid proteins by electrofocusing and by electrophoretic mobility of the genomic poly(C)-rich tract suggested heterogeneity in several isolates and sequential dominance of viral subpopulations. Nucleotide sequences of the VP1-coding region of the parental FMDV C3 clones and of seven isolates from the carrier cattle showed point mutations that represented rates of fixation of mutations of 0.9 X 10(-2) to 7.4 X 10(-2) substitutions per nucleotide per year; 59% of the base changes led to amino acid substitutions, some of which were located within residues 135 to 151, a region involved in neutralization of FMDV. In the esophageal pharyngeal fluid samples, FMDV C3-neutralizing activity was present. Antigenic variation was demonstrated with monoclonal antibodies raised against FMDV C3. Two isolates from carrier cattle differed from the parental virus by 10(2)- or 10(3)-fold decreased reactivity with neutralizing monoclonal antibodies. We suggest that persistent, inapparent infections of ruminants, in addition to being a reservoir of virus, may promote the rapid selection of antigenically variant FMDVs.

Microbial agents of the owl monkey (Aotus trivirgatus).

A survey of the microbial flora in the owl monkey (Aotus trivirgatus) has led to the isolation of numerous bacterial, fungal, and viral agents. Some of the bacterial and fungal agents, particularly Dermatophilus, Pasteurella, Salmonella, Shigella, Yersinia, Streptococcus, Staphylococcus, and Candida are known pathogens. Viruses belonging to the herpesvirus, adenovirus, paramyxovirus, and papovavirus groups have been isolated from the owl monkey. Most of these viruses were recovered as latent agents from kidney cell cultures. Thus far, they have not been associated with clinical illness or specific lesions in the owl monkey and their infectivity for other animal hosts and for man is unknown.

The owl monkey (Aotus trivirgatus) as an animal model for viral diseases and oncologic studies.

The owl monkey (Aotus trivirgatus) has been shown to be an excellent model for studies of oncogenic and non-oncogenic viruses. Studies at this institution have been primarily concerned with Herpesvirus saimiri, the Epstein-Barr virus, H tamarinus, and H simplex. These studies have shown that H saimiri is oncogenic when inoculated into primates, that the malignancy induced by H saimiri can be naturally transmitted from the squirrel monkey to the owl monkey, that in vitro pathogenicity of H saimiri can be modified by passing the virus in a nonpermissive cellular host, that the owl monkey is a useful model for studying the oncogenicity of the Epstein-Barr virus, and the fatal disease induced in owl monkeys by H tamarinus and H simplex can be prevented by vaccination with nonpathogenic variants of these viruses.