The role of unpasteurized "hawked" milk in the transmission of brucellosis in Eldoret municipality, Kenya.

Background: Brucellosis is a zoonotic disease that continues to infect many people worldwide. Though its mortality rate is low, long convalescent periods associated with brucellosis translate into reduced socio-economic capacity of the people affected. Human brucellosis is mostly transmitted from animals.

Evaluation of Non-radioactive ELISA assay Kits for Detection of Retroviral Reverse Transcriptase (RT) Activity Associated with Retroviral SIV and HIV.

Reverse transcriptase (RT) assay is commonly used to detect enzyme activity associated with retroviral-like particles. Previously, detection of RT activity in virus-infected cultures was done using a radioisotope-based assay system. However, assay systems, which detect the antigen directly(as opposed to antibody ELISA assays), have been developed.

Evaluation of HIV ELISA diagnostic kit developed at the Institute of Primate Research, Nairobi, Kenya.

The first diagnostic kits utilizing the enzyme-linked immunosorbent assay (ELISA) technique were developed in mid-eighties, and since then, this technique has become an increasingly important tool for screening multiple samples of blood or serum for presence of antibodies to various infectious pathogens, especially human immunodeficiency virus (HIV) in blood banks. However, most of the commercial diagnostic kits currently available in the market are too expensive, hence not easily affordable in most Diagnostic Laboratories. We designed an ELISA kit for diagnosis of HIV and compared it with some of the commercial kits.

Viral load, CD4+ T-lymphocyte counts and antibody titres in HIV-1 infected untreated children in Kenya; implication for immunodeficiency and AIDS progression.

Background: There are limited reports on HIV-1 RNA load, CD4+ T-lymphocytes and antibody responses in relation to disease progression in HIV-1 infected untreated children in Africa.

Methods: To describe the relationships between these parameters, we conducted a longitudinal cohort study involving 51 perinatally HIV-1 infected children aged between 1 and 13 years. HIV status was determined by ELISA and confirmed by western blot and PCR.

Seroprevalence of simian immunodeficiency virus in wild and captive born Sykes' monkeys (Cercopithecus mitis) in Kenya.

Background: The Sykes' monkey and related forms (Cercopithecus mitis) make up an abundant, widespread and morphologically diverse species complex in eastern Africa that naturally harbors a distinct simian immunodeficiency virus (SIVsyk). We carried out a retrospective serological survey of SIV infection from both wild and captive Sykes' monkeys from Kenya. We compared two commercially available, cross-reactive ELISA tests using HIV antigens with a novel SIVsyk antigen-specific Western blot assay and analyzed the data by origin, subspecies, age and sex.

Oxidative stress in rats after 60 days of hypergalactosemia or hyperglycemia.

Two of the models used in current diabetes research include the hypergalactosemic rat and the hyperglucosemic, streptozotocin-induced diabetic rat. Few studies, however, have examined the concurrence of these two models regarding the effects of elevated hexoses on biomarkers of oxidative stress. This study compared the activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase and the concentrations of glutathione, glutathione disulfide, and thiobarbituric acid reactants (as a measure of lipid peroxidation) in liver, kidney, and heart of Sprague-Dawley rats after 60 days of either a 50% galactose diet or insulin deficiency caused by streptozotocin injection.

Effect of menstrual cycle on mucosal immunity to SHIV within the reproductive tract of baboons (Papio anubis): preliminary findings.

The presence of human immunodeficiency virus (HIV) in genital secretions is regarded as a risk factor for sexual and perinatal transmission of HIV. A better understanding of correlates of genital shedding of HIV is crucial to the development of effective strategies against transmission of this virus. Events during menstrual cycle are likely to influence local immune responses and viral load in genital secretions, and hence determine susceptibility to HIV or efficiency of virus transmission.

Characterization of oxidative stress in various tissues of diabetic and galactose-fed rats.

Rats fed a galactose-rich diet have been used for several years as a model for diabetes to study, particularly in the eye, the effects of excess blood hexoses. This study sought to determine the utility of galactosemia as a model for oxidative stress in extraocular tissues by examining biomarkers of oxidative stress in galactose-fed rats and experimentally-induced diabetic rats. Sprague-Dawley rats were divided into four groups: experimental control; streptozotocin-induced diabetic; insulin-treated diabetic; and galactose-fed.

Neutralizing antibody responses in Africa green monkeys naturally infected with simian immunodeficiency virus (SIVagm).

This study assessed the magnitude and cross-reactivity of the neutralizing antibody response generated by natural SIV infection in wild-caught African green monkeys. Neutralizing antibodies of variable potency, sometimes exceeding a titer of 1:1,000, were detected in 20 of 20 SIV-seropositive African green monkeys in Kenya. Detection of those neutralizing antibodies was dependent on the strain of virus and the cells used for assay, where the most sensitive detection was made with SIVagm1532 in Sup T1 cells.

Helminth and protozoan gastrointestinal tract parasites in captive and wild-trapped African non-human primates.

The objective of this study was to investigate the gastro-intestinal (GIT) parasites commonly occurring in captive and wild-trapped (WT) non-human primates (baboons, vervets and Sykes) in Kenya and compare their prevalence. Three hundred and fifteen faecal samples were subjected to a battery of diagnostic tests, namely, direct smear, modified formal ether sedimentation, Kato thick smear, Harada-Mori techniques for parasite detection and culture to facilitate nematode larvae identification. Of these, 203 (64.

Cytomegalovirus and simian immunodeficiency virus coinfection: longitudinal study of antibody responses and disease progression.

Antibody titers to rhesus cytomegalovirus (RhCMV) were prospectively analyzed over a period of 68 weeks in a longitudinal serosurvey of 17 RhCMV-seropositive rhesus macaques (Macaca mulatta) experimentally coinfected with simian immunodeficiency virus (SIV). These were compared with anti-RhCMV titers in 18 animals that were also naturally infected with RhCMV but not infected with SIV. Fluctuations in anti-RhCMV antibody titers were observed within 5 weeks of SIV inoculation, and two distinct patterns of RhCMV antibody response were observed in SIV-infected animals.

A zidovudine-resistant simian immunodeficiency virus mutant with a Q151M mutation in reverse transcriptase causes AIDS in newborn macaques.

The simian immunodeficiency virus (SIV)-newborn rhesus macaque model of AIDS can be used to study directly the virulence of viral mutants which are resistant to antiviral drugs. A viral mutant called SIVmac79A6.1, isolated from an SIV-infected macaque after prolonged zidovudine treatment, was found to have a double-base-pair change at codon 151 of reverse transcriptase, resulting in a glutamine to methionine substitution (Q151M).

Fetal or neonatal infection with attenuated simian immunodeficiency virus results in protective immunity against oral challenge with pathogenic SIVmac251.

We have reported that infection of fetal or neonatal rhesus macaques with attenuated SIVmac1A11 results in transient viremia, anti-SIV antibody responses, weak or absent cytotoxic T-lymphocyte responses, and no clinical disease. In light of these results, we hypothesized that congenital infection with SIVmac1A11 produced immune tolerance to SIV. To test this hypothesis, at approximately 1 year of age, five rhesus macaques infected with SIVmac1A11 as fetuses (n = 3) or newborns (n = 2) and five naive juvenile rhesus macaques were challenged orally with pathogenic SIVmac251.

Vaccination of pregnant macaques protects newborns against mucosal simian immunodeficiency virus infection.

Simian immunodeficiency virus (SIV) infection of newborn rhesus macaques is a rapid, sensitive animal model of human pediatric AIDS. Newborn macaques were readily infected by uncloned SIVmac following oral-conjunctival exposure and had persistently high viremia and rapid development of AIDS. In contrast, when 3 pregnant macaques were vaccinated against SIV, 2 of the newborns that had transplacentally acquired antiviral antibodies were protected against mucosal SIV infection at birth.

Virus-induced immunosuppression is linked to rapidly fatal disease in infant rhesus macaques infected with simian immunodeficiency virus.

Six newborn rhesus macaques were experimentally infected with pathogenic Simian immunodeficiency virus of macaques (SIVmac251), and three newborn macaques were infected with avirulent SIVmac1A11. The former developed rapidly fatal simian AIDS and died within 26 wk of age, whereas the latter remained clinically normal. Infant monkeys that developed rapidly progressive disease had rapid declines in CD4+ cells and were unable to mount IgG and IgA antibody responses to SIV or to an unrelated antigen, tetanus toxoid.

Immunoassay for detection of antibodies to simian immunodeficiency virus and human immunodeficiency virus in serum.

We developed a simple, inexpensive, rapid assay for the detection of antibodies to simian immunodeficiency virus (SIV) and human immunodeficiency virus type 1 (HIV-1) in serum. The immunoassay uses inactivated SIV and HIV-1 gp41 transmembrane recombinant protein as antigenic adsorbents on a nitrocellulose filter membrane. Diluted serum, with the addition of Protein-A-Gold, is gravity-filtered through the filter membrane, blocked, and buffer-washed.

Prevalence of antibodies against simian immunodeficiency virus (SIV) and simian T-lymphotropic virus (STLV) in a colony of non-human primates in Kenya, East Africa.

Sera (165 samples in 1988 and 66, follow-up samples in 1989) were collected from olive baboons, African green monkeys, Syke's monkeys and grey mangabeys kept in a semi-free, breeding colony at the Institute of Primate Research (IPR) in Nairobi, Kenya. The levels of antibodies to simian T-lymphotropic virus (STLV) or simian immunodeficiency virus (SIV), and the reactivity patterns of positive sera to various lentivirus subgroup antigens, were then determined. The results of tests using enzyme-immunoassay kits were confirmed by western blots.

Viral factors determine progression to AIDS in simian immunodeficiency virus-infected newborn rhesus macaques.

To evaluate how viral variants may affect disease progression in human pediatric AIDS, we studied the potential of three simian immunodeficiency virus (SIV) isolates to induce simian AIDS in newborn rhesus macaques. The three virus isolates were previously shown to range from pathogenic (SIVmac251 and SIVmac239) to nonpathogenic (SIVmac1A11) when inoculated intravenously into juvenile and adult rhesus macaques. Six newborn macaques inoculated with pathogenic, uncloned SIVmac251 developed persistent, high levels of cell-associated and cell-free viremia, had no detectable antiviral antibodies, and had poor weight gain; these animals all exhibited severe clinical disease and pathologic lesions diagnostic for simian AIDS and were euthanatized 10 to 26 weeks after inoculation.

Immediate zidovudine treatment protects simian immunodeficiency virus-infected newborn macaques against rapid onset of AIDS.

Simian immunodeficiency virus (SIV) infection of newborn rhesus macaques is a practical animal model of pediatric AIDS. Intravenous inoculation of rhesus newborns with uncloned SIVmac resulted in a high virus load, no antiviral immune responses, severe immunodeficiency, and a high mortality rate within 3 months. In contrast, immediate oral zidovudine (AZT) treatment of SIV-inoculated rhesus newborns either prevented infection or resulted in reduced virus load, enhanced antiviral immune responses, a low frequency of AZT-resistant virus isolates, and delayed disease progression with negligible toxicity.

Mucosal immunization with a live, virulence-attenuated simian immunodeficiency virus (SIV) vaccine elicits antiviral cytotoxic T lymphocytes and antibodies in rhesus macaques.

An effective AIDS vaccine must protect against sexual transmission of human immunodeficiency virus (HIV). Therefore, vaccine regimens which stimulate antiviral immunity in the genital tract as well as in peripheral blood and systemic lymphoid tissues are needed. Here, we describe a method of immunization by direct inoculation of the vaginal submucosa with a live attenuated SIV, SIVmac1A11.

Trypanosomal antigen and antibody levels in field camels following treatment with two trypanocidal drugs.

The efficacy of treatment in 61 naturally trypanosome-infected camels was evaluated by antigen and antibody detection. Following treatment of 14 infected field camels with an arsenical drug (RM110) no trypanosomal antigens could be detected in the animals which were treated with 0.6 mg/kg body weight and 1.