Identification of a human population infected with simian foamy viruses.

Studying the transmission of simian retroviruses to humans can help define the importance of these infections to public health. We identified a substantial prevalence (4/231, 1.8%) of infection with simian foamy viruses (SFV) among humans occupationally exposed to nonhuman primates. Evidence of SFV infection included seropositivity, proviral DNA detection and isolation of foamy virus. The infecting SFV originated from an African green monkey (one person) and baboons (three people). These infections have not as yet resulted in either disease or sexual transmission, and may represent benign endpoint infections.

Simian AIDS: isolation of a type D retrovirus and transmission of the disease.

A type D retrovirus related to but distinct from Mason-Pfizer monkey virus was isolated in vitro from the blood of two rhesus monkeys (Macaca mulatta) with simian acquired immunodeficiency syndrome (SAIDS). Three juvenile rhesus monkeys that were injected intravenously with tissue culture fluids containing this virus developed SAIDS after 2 to 4 weeks.

Natural history of endemic type D retrovirus infection and acquired immune deficiency syndrome in group-housed rhesus monkeys.

A 2.5-year epidemiologic study of a breeding group of rhesus monkeys (Macaca mulatta), which is a focus of endemic simian acquired immunodeficiency syndrome (SAIDS), demonstrated a strong association between the occurrence of SAIDS and infection with a type D retrovirus, SAIDS retrovirus serotype 1 (SRV-1). Of 23 healthy "tracer" juvenile rhesus monkeys, 19 (83%) died with SAIDS within 9 months of introduction into the resident SAIDS-endemic population. In contrast, 21 healthy "sentinel" juvenile rhesus monkeys placed in the same outdoor enclosure but denied physical contact with the SAIDS-affected group by a 10-foot-wide "buffer zone" remained free of SRV-1, SRV-1 antibody, and disease for 2.5 years. The SAIDS-specific mortality rate was significantly higher in juveniles than in adults. In repeated serologic testing, the overall prevalence of SRV-1 antibody ranged from 68 to 85%. Antibody prevalence increased with age. Seroconversion was found to be a poor indicator of infection rate, as approximately 50% of virus-positive juvenile monkeys had no antibody detectable by enzyme-linked immunosorbent assay. Repeated viral isolations from all animals revealed 1) SRV-1 viremia with clinical SAIDS; 2) persistent viremia and viral shedding in apparently healthy animals; 3) transient viremia and clinical recovery; 4) intermittent viremia, suggesting activation of latent infections; and 5) viremia in a 1-day-old infant, suggesting transplacental transmission. The prevalence of SRV-1 antibody in SAIDS-free breeding groups of rhesus monkeys was 4%. The seroprevalence of antibodies against human T-cell leukemia virus type 1 (HTLV-1), human immunodeficiency virus (HIV), and simian immunodeficiency virus (SIV; formerly STLV-III) was uniformly low or absent in both SAIDS-free and SAIDS-affected groups of rhesus monkeys, demonstrating that these retroviruses are not etiologically linked to SAIDS at the California Primate Research Center.

Inapparent carriers of simian acquired immune deficiency syndrome type D retrovirus and disease transmission with saliva.

Simian acquired immune deficiency syndrome (SAIDS) type D retrovirus (SRV) was isolated from saliva, urine, and peripheral blood mononuclear cells of a 6-year-old healthy rhesus monkey (Macaca mulatta) seronegative for antibodies to human T-lymphotropic virus (HTLV) type I, HTLV type III, and simian T-lymphotropic virus type III (STLV-III), identified as an inapparent SAIDS carrier in retrospective epidemiologic studies. This animal was linked to 34 cases of SAIDS over a 3-year period. Two juvenile rhesus monkeys inoculated iv with the SRV-containing saliva from this carrier became persistently infected with the retrovirus and developed SAIDS after 4-6 weeks. Both animals seroconverted to SRV, but neither had detectable preinoculation or postinoculation antibodies against HTLV type I, HTLV type III, or STLV-III. One of these animals died of SAIDS with disseminated cytomegalovirus infection after 24 weeks, and the other remains alive with persistent SRV viremia, generalized lymphadenopathy, and splenomegaly after a transient immunosuppression. Major clinical and pathological features associated with the newly described STLV-III were not observed. SRV was subsequently identified in saliva of 2 additional healthy carriers as well as monkeys with SAIDS. The findings of a carrier state in SAIDS and evidence for saliva transmission of the probable causative virus further support the usefulness of this animal model of nononcogenic immunosuppressive retroviral disease.

Immunodeficiency in rhesus monkeys associated with the original Mason-Pfizer monkey virus.

The Mason-Pfizer monkey virus (MPMV) was reisolated from a cryopreserved sample of the original MPMV-containing rhesus breast carcinoma, and complete integrated MPMV provirus was detected in chromosomal DNA of this tumor. Reanalysis of the in vivo pathogenicity and molecular character of MPMV reisolated from the rhesus breast tumor and analysis of the original MPMV after long-term in vitro propagation in human and rhesus cells show that the original MPMV produces an acquired immunodeficiency similar to that caused by the recently described simian acquired immune deficiency syndrome type D retroviruses, and the MPMV genome and its immunosuppressive effect in vivo have remained stable despite prolonged in vitro passage in human and rhesus cells.

Psychosocial factors and disease progression in simian AIDS: a preliminary report.

Infection of macaques by the simian immunodeficiency virus (SIV), like HIV infection in humans, results in a variable time course to clinical disease. Developmental studies of macaques have shown that psychosocial disruption, including social separations, can result in both immediate and long-term immunological consequences. Using colony records on a subset of rhesus macaques (Macaca mulatta) inoculated with SIV at the California Primate Research Center, Davis, California, USA, we constructed regression equations to determine whether the animals' psychosocial histories could explain any of the variability observed in measures of disease progression. After controlling for dosage, age at inoculation, sex, and previous inoculation history, psychosocial variables were found to be significantly associated with several indicators of disease, including latencies to display leukopenia and lymphopenia, weight loss, and survival. We believe these preliminary results suggest an important role for psychosocial processes in affecting disease progression in SIV infection in macaques.

The search for human infection with simian type D retroviruses.

Evidence has recently been presented for an infection with a simian type D retrovirus in a patient with AIDS and lymphoma. We tested for simian type D infection in three groups of subjects: 375 patients with lymphoproliferative diseases (255 non-Hodgkin's, 88 Hodgkin's, and 32 chronic lymphoproliferative disease), of whom 75 were human immunodeficiency virus (HIV)-1 infected; seven persons with unexplained low CD4 lymphocyte counts with clinical conditions; and 45 blood donors, of whom 37 were human T-lymphocyte virus (HTLV)-I/II seroindeterminate and eight were HTLV-I/II and HIV-1 seronegative. Serum samples were screened for antibodies against simian type D retroviruses by an enzyme immunoassay, and reactive samples were analyzed by Western blotting. None of the samples were seropositive, but eight (five from non-Hodgkin's and three from Hodgkin's lymphoma patients) were seroindeterminate. Polymerase chain reaction analysis of genomic DNA from peripheral blood lymphocytes of all eight of these patients was carried out using simian type D gag generic primers with generic internal oligoprobing. All samples were negative. We conclude that simian type D infection is rare among HIV-infected and noninfected lymphoma patients, persons with unexplained low CD4 counts, and persons with HTLV-seroindeterminate test results.

Pseudomonas fluorescens bacteremia from blood transfusion.

In October 1980, two units of blood contaminated with Pseudomonas fluorescens caused septic transfusion reactions in two recipients at a Chicago hospital; one patient died. Both units had been purchased from the same blood center. Investigation at the blood center and at other hospitals it supplied revealed another fatal case of P. fluorescens sepsis that had occurred one year earlier. Despite extensive environmental culturing at the blood center, the source of P. fluorescens was not identified. However, comparison of the interval between collection and administration of contaminated and non-contaminated units indicated that prolonged storage was a risk factor that may have caused clustering of cases in one hospital. Laboratory studies showed that small inocula of P. fluorescens proliferated in refrigerated fresh whole blood and reached 10(6) to 10(7) colony-forming units per milliliter seven days after incubation. These data suggest that prolonged storage of blood may be an important risk factor for the development of transfusion-related sepsis.

Simultaneous detection of simian retrovirus type D serotypes 1, 2, and 3 by polymerase chain reaction.

Asymptomatic infection of macaques with macaques with simian retroviruses type D (SRV/D), the etiologic agents of one form of retrovirus-induced simian immunodeficiency disease, can confound experiments with the simian immunodeficiency virus (SIV), which also induces immunodeficiency disease in macaques. The SIV/macaque model is the preferred nonhuman primate model for AIDS-related research. Serological screening for SRV/D alone is insufficient because not all infected animals seroconvert, and virus isolation by cocultivation may require 4 to 6 weeks. We have established a DNA polymerase chain reaction (PCR) assay. One set of nested primers allows detection of SRV/D serotypes 1, 2, and 3 and distinguishes SRV-2 from the other two serotypes. The PCR assay is sensitive; a single proviral copy of SRV/D could be detected in 150,000 to 210,000 macaque peripheral blood mononuclear cells (PBMCs). When applied to a panel of virus isolation-positive macaque samples, the PCR assay was positive in 100% of the tests. No false-positive results were seen when known specific-pathogen-free (SPF) macaques were examined. We propose that macaques be screened with a combination of SRV/D serology and this DNA PCR assay prior to enrollment in experiments with SIV.

SIV, STLV-I and type D retrovirus antibodies in captive rhesus macaques and immunoblot reactivity to SIV p27 in human and rhesus monkey sera.

The prevalence of simian immunodeficiency virus (SIV), simian T-cell lymphotropic virus type 1 (STLV-I), and type D retrovirus (SRV-D) antibodies was determined for 1229 rhesus monkeys (Macaca mulatta) from two research colonies. Serum samples were tested by using enzyme-linked immunosorbent assay (ELISA), immunoblot (IB), and radioimmunoprecipitation assay (RIPA). Seropositive results for the three retroviruses tested were 0 for SIV, 270 (22%) for STLV-I, and 103 (8.4%) for type D retrovirus. Of the rhesus monkey sera, 61 (5.0%) were reactive to SIV gag p27 only, when tested by IB, but were negative when further tested by RIPA. Virus isolation was attempted from cultured peripheral blood mononuclear cells of 35 monkeys whose sera contained only p27 reactivity and none were positive by reverse transcriptase and core antigen assays to detect SIV. No overt clinical signs of immunodeficiency disease or unexplained deaths were evident in either monkey colony. Additionally, 63 of 165 (38%) human sera from various groups (primate center workers, normal donors, health care workers) had weak to moderate IB reactivity only to SIV p27, but 31 of 31 sera tested were negative by RIPA. These sera remained reactive to SIV p27 following absorption with an uninfected cell lysate, after blocking IB strips with various blocking solutions and were reactive to different SIV antigen preparations while remaining negative to human immunodeficiency virus type 1 (HIV-1) by IB and negative to HIV-2 by ELISA. These data underscore the need to adopt criteria for a positive SIV serologic test requiring reactivity against more than one viral gene product. These results also illustrate a potential problem in the testing of human sera for antibodies against simian retroviruses and demonstrate the need for caution in the interpretation of immunoblot results.

A simian model of human granulocytic ehrlichiosis.

Following intravenous inoculation with horse blood-infected with the agent of human granulocytic ehrlichiosis (HGE) from a human fatality, two rhesus macaques (Macaca mulatta) exhibited pyrexia and lethargy on days 4-12 postinfection (PI). Hematology revealed neutropenia, thrombocytopenia, and anemia, with ehrlichial morulae in monocytes and neutrophils on days 4-12. Blood was polymerase chain reaction (PCR)-positive on days 4-12 and bone marrow was PCR-positive on day 11. There was a minor increase in gamma-glutamyl transpeptidase on day 12 and serum interferon-gamma levels increased by day 18. Seroconversion occurred on day 20 PI to a titer of 100 by day 22. Western blot bands characteristic of HGE included 25-, 44-, 80-, 94-, 105-, and 125-kD bands. There was generalized lymphohistiocytic infiltration in the liver, spleen, lymph nodes, and other tissues. The liver had focal hepatocyte apoptosis. There was HGE DNA (by PCR) only in the spleen. Comparable findings were not observed in a monkey that received uninfected horse blood as a control. This animal model of human disease is important for further studies of HGE diagnosis, management, and pathogenesis.

Evidence of natural bluetongue virus infection among African carnivores.

Bluetongue is an International Office of Epizootics List A disease described as the century's most economically devastating affliction of sheep. Bluetongue (BLU) viruses were thought to infect only ruminants, shrews, and some rodents, but recently, inadvertent administration of BLU virus-contaminated vaccine resulted in mortality and abortion among domestic dogs. We present evidence of natural BLU virus infection among African carnivores that dramatically widens the spectrum of susceptible hosts. We hypothesize that such infection occurred after ingestion of meat and organs from BLU virus-infected prey species. The effect of BLU virus on endangered carnivores such as the cheetah and African wild dog requires urgent investigation. Also, the role of carnivores in the epizootiology of this disease needs elucidation.

Mamu-DQA1 allele and genotype frequencies in a randomly sampled breeding colony of rhesus macaques (Macaca mulatta).

We studied the allelic and genotypic distribution of the major histocompatibility class-II locus DQA1 observed in a random sample of Indian rhesus macaques (Macaca mulatta) from a major breeding facility in the United States. The DNA was isolated from whole blood samples collected between 1991 and 1994 from 65 Indian rhesus monkeys. Polymerase chain reaction-restriction fragment length polymorphism analysis (PCR-RFLP), which involves use of specific amplification of DQA1 exon 2 and subsequent restriction digestion of the 242-base pair fragment, was used to genotype the animals for the 20 known macaque (Mamu)-DQA1 alleles. Frequencies for four alleles (DQA1*240x, *2502, *2503 and *0102) differed significantly from those reported in a smaller sample of rhesus macaques from the German Primate Center. The modest genetic survey of Mamu-DQA1 genotypes presented here will be particularly useful in designing epidemiologic studies that investigate associations between immunogenetic background and disease susceptibility in macaque models of human disease.

Atypical crusted "Norwegian" scabies: report of nosocomial transmission in a community hospital and an approach to control.

During August, 1981, a person with an unrecognized case of atypical Norwegian scabies was admitted to a community hospital in Chariton, Iowa. Twenty cases of symptomatic scabies were reported among hospital staff; mites were recovered from four. Subsequent evaluation confirmed scabies transmission to family and friends of this patient before hospitalization; twelve cases of symptomatic scabies, three of them slide positive, were identified in this group. The patient was treated sequentially with 1 percent lindane lotion, 10 percent crotamiton lotion, and 6 percent sulfur ointment to successfully eradicate the infestation. Secondary cases in the hospital and community were treated with 10 percent crotamiton which also was used to prophylactically treat exposed contacts. Control measures and patient management are presented.

Pathogenesis of simian AIDS in rhesus macaques inoculated with the SRV-1 strain of type D retrovirus.

Type D retrovirus was isolated from rhesus macaques with simian acquired immunodeficiency syndrome (SAIDS) and transmitted to healthy rhesus macaques with tissue culture medium containing the virus. The clinical, immunologic, and lymph node morphologic changes were observed in 9 rhesus macaques for 52 weeks after inoculation. A spectrum of clinical signs developed including early death, persistent SAIDS, and apparent remission. Animals that died or developed persistent SAIDS had characteristic lymphoid depletion, persistently depressed peripheral blood mononuclear cell (PBMC) mitogenic response, and decreased serum immunoglobulins. The SAIDS retrovirus (SRV) was recovered from PBMC of 8 of the animals after inoculation. Virus could not be recovered from PBMC of one animal in remission, but this animal developed serum-neutralizing antibodies to SRV after inoculation. Seven of the animals seroconverted to SRV after inoculation, all 9 were seronegative for human T-lymphotropic virus-III, and 5 animals tested were seronegative to human T-lymphotropic virus-I. These findings support the etiologic role of the type D retrovirus in SAIDS and further define the pathogenesis of this disease.

Electrolyte abnormalities associated with diarrhea in rhesus monkeys: 100 cases (1986-1987).

Serum electrolyte values from 100 rhesus monkeys with diarrhea were reviewed. The most frequent finding was hyponatremia (88%), with hypochloremia next most frequently detected (80%). Metabolic acidosis was less common (59%) and usually associated with high anion gap values. Associations between electrolyte abnormalities and age, housing, or case outcome were not found. Bacteriologic culturing was performed on fecal specimens from 90 monkeys. Campylobacter coli or C jejuni alone was isolated from 42 (46.7%) specimens, C coli and Shigella flexneri were isolated from 25 (27.8%) specimens, and S flexneri alone was isolated from 6 (6.7%) specimens. A pathogen was not isolated from 17 (18.9%) specimens. Hyponatremia, hypochloremia, acidosis, and high anion gap values were most severe in monkeys infected with Campylobacter sp, either alone or with concurrent S flexneri infection. Serum sodium concentrations less than 132 mEq/L and serum Cl concentrations less than 93 mEq/L were consistently associated with Campylobacter sp infection.

Yersinia pseudotuberculosis infection in a group of Macaca fascicularis.

Diarrheal disease associated with abortions and stillbirths occurred in a group of 42 Macaca fascicularis. The group was composed of wild-caught adults and their colony-born offspring housed in a half-acre cage. Thirteen adult females and 1 infant male were affected. All 14 monkeys had diarrhea and all 9 pregnant females either aborted or had a stillbirth. Yersinia pseudotuberculosis was isolated from 7 animals. In addition, Y enterocolitica was isolated from 1 monkey and Shigella flexneri type IV was isolated from 5 monkeys. One adult female had a mixed infection of both Y pseudotuberculosis and S flexneri. Every pregnant monkey from which Y pseudotuberculosis was isolated aborted or had a stillbirth. Five animals died, and Y pseudotuberculosis was the only pathogen isolated from these 5 monkeys.

Eradication of simian retrovirus type D from a colony of cynomolgus, rhesus, and stump-tailed macaques by using serial testing and removal.

The markedly compromised health of animals in a macaque colony and the problematic interpretation of data from two drug safety assessment studies prompted a review of the effect of simian retrovirus type D on the drug-development process at a Midwest pharmaceutical company. After reviewing relevant literature and consulting with an expert in simian retroviruses, we initiated a program of eradication. During a 16-month period, all cynomolgus (Macaca fascicularis), rhesus (Macaca mulatta), and stump-tailed (Macaca arctoides) macaques housed in the facility were evaluated as many as eight times for the presence of simian retrovirus type D by using serology, virus isolation, and/or polymerase chain reaction tests. All animals with positive test results were removed from the colony immediately. No test results indicative of simian retrovirus type D infection have occurred during the subsequent 2.5 years. We attribute the successful eradication and prevention of re-introduction of the virus to regular testing, purchasing animals from sources free of simian retrovirus type D, and assiduous application of procedures designed to prevent transmission between animals.