Fatal measles virus infection in Japanese macaques (Macaca fuscata)

Markers of antroponotic viral infections in vervet monkeys arrived from their natural habitat (Tanzania)

INTRODUCTION

Various human viruses have been identified in wild monkeys and in captive primates. Cases of transmission of viruses from wild monkeys to humans and vice versa are known. The aim of this study was to identify markers of anthroponotic viral infections in vervet monkeys (Chlorocebus pygerythrus) arrived from their natural habitat (Tanzania).

MATERIALS AND METHODS

Fecal samples (n = 56) and blood serum samples (n = 75) obtained from 75 animals, respectively, on days 10 and 23 after admission to the primate center, were tested for the markers of anthroponotic viral infections (Ebola virus, Marburg virus, lymphocytic choriomeningitis, hepatitis C virus, herpes simplex virus (HSV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), parainfluenza types 1 and 3, intestinal adenoviruses, rotaviruses) by enzyme immunoassay (ELISA) and polymerase chain reaction (PCR).

RESULTS AND DISCUSSION

Among the examined animals, markers of 6 out of 11 tested viral infections were identified. Detection rates of IgG antibodies to HSV-1,2 (15.9%) and CMV (15.9%) were two times as low as IgG antibodies to EBV (31.8%). Among the markers of respiratory viral infections, IgG antibodies to parainfluenza virus type 1 were found (6.8%). 14.3% of the animals had rotavirus antigen, and 94% had simian adenovirus DNA. Markers of hemorrhagic fevers Ebola, Marburg, LCM, hepatitis C, and type 3 parainfluenza were not detected.

CONCLUSION

When importing monkeys from different regions of the world, an expanded screening for viral infections is needed considering the epidemiological situation both in the country of importation and in the country of destination.

Pathologic characteristics of infectious diseases in macaque monkeys used in biomedical and toxicologic studies

Nonhuman primates (NHPs), which have many advantages in scientific research and are often the only relevant animals to use in assessing the safety profiles and biological or pharmacological effects of drug candidates, including biologics. In scientific or developmental experiments, the immune systems of animals can be spontaneously compromised possibly due to background infection, experimental procedure-associated stress, poor physical condition, or intended or unintended mechanisms of action of test articles. Under these circumstances, background, incidental, or opportunistic infections can seriously can significantly complicate the interpretation of research results and findings and consequently affect experimental conclusions. Pathologists and toxicologists must understand the clinical manifestations and pathologic features of infectious diseases and the effects of these diseases on animal physiology and experimental results in addition to the spectrum of infectious diseases in healthy NHP colonies. This review provides an overview of the clinical and pathologic characteristics of common viral, bacterial, fungal, and parasitic infectious diseases in NHPs, especially macaque monkeys, as well as methods for definitive diagnosis of these diseases. Opportunistic infections that can occur in the laboratory setting have also been addressed in this review with examples of cases of infection disease manifestation that was observed or influenced during safety assessment studies or under experimental conditions.

Measles in non-human primates

It is six decades since the measles vaccine was first introduced, and yet we continue to see frequent outbreaks of this disease occurring all over the world. Many non-human primate (NHP) species, including apes, are susceptible to the measles virus. Spontaneous measles outbreaks have been described in a number of zoos and primate centers worldwide. Research into the spontaneous and experimental infection of laboratory primates with measles represents an invaluable source of information regarding the biology and pathogenesis of this virus and continues to be an irreplaceable and unique tool for testing vaccines and treatments. The purpose of this literature review is to summarize and analyze published data on the circulation of the measles virus among free-living synanthropic and captive primate populations, as well as the results of experiments that have modeled this infection in NHPs.

Phenotypic and Transcriptional Changes of Pulmonary Immune Responses in Dogs Following Canine Distemper Virus Infection

Canine distemper virus (CDV), a morbillivirus within the family Paramyxoviridae, is a highly contagious infectious agent causing a multisystemic, devastating disease in a broad range of host species, characterized by severe immunosuppression, encephalitis and pneumonia. The present study aimed at investigating pulmonary immune responses of CDV-infected dogs in situ using immunohistochemistry and whole transcriptome analyses by bulk RNA sequencing. Spatiotemporal analysis of phenotypic changes revealed pulmonary immune responses primarily driven by MHC-II⁺, Iba-1⁺ and CD204⁺ innate immune cells during acute and subacute infection phases, which paralleled pathologic lesion development and coincided with high viral loads in CDV-infected lungs. CD20⁺ B cell numbers initially declined, followed by lymphoid repopulation in the advanced disease phase. Transcriptome analysis demonstrated an increased expression of transcripts related to innate immunity, antiviral defense mechanisms, type I interferon responses and regulation of cell death in the lung of CDV-infected dogs. Molecular analyses also revealed disturbed cytokine responses with a pro-inflammatory M1 macrophage polarization and impaired mucociliary defense in CDV-infected lungs. The exploratory study provides detailed data on CDV-related pulmonary immune responses, expanding the list of immunologic parameters potentially leading to viral elimination and virus-induced pulmonary immunopathology in canine distemper.

Common and Not-So-Common Pathologic Findings of the Gastrointestinal Tract of Rhesus and Cynomolgus Macaques

Rhesus and cynomolgus macaques are the most frequently used nonhuman primate (NHP) species for biomedical research and toxicology studies of novel therapeutics. In recent years, there has been a shortage of laboratory macaques due to a variety of competing factors. This was most recently exacerbated by the surge in NHP research required to address the severe acute respiratory syndrome (SARS)-coronavirus 2 pandemic. Continued support of these important studies has required the use of more varied cohorts of macaques, including animals with different origins, increased exposure to naturally occurring pathogens, and a wider age range. Diarrhea and diseases of the gastrointestinal tract are the most frequently occurring spontaneous findings in macaques of all origins and ages. The purpose of this review is to alert pathologists and scientists involved in NHP research to these findings and their impact on animal health and study endpoints, which may otherwise confound the interpretation of data generated using macaques.

[Prevalence of laboratory markers of human respiratory viruses in monkeys of Adler primate center]

INTRODUCTION

The relevance of studying the circulation of human respiratory viruses among laboratory primates is associated with the need to test vaccines and antiviral drugs against these infections on monkeys.The aim of this work was to study the prevalence of serological and molecular markers of human respiratory viral infections in laboratory primates born at the Adler Primate Center and in imported monkeys.

MATERIAL AND METHODS

Blood serum samples (n = 1971) and lung autopsy material (n = 26) were obtained from different monkey species. These samples were tested for the presence of serological markers of measles, parainfluenza (PI) types 1, 2, 3, influenza A and B, respiratory syncytial (RS) and adenovirus infections using enzyme immunoassay (ELISA). Detection of RS virus, metapneumovirus, PI virus types 1-4, rhinovirus, coronavirus, and adenoviruses B, C, E and bocavirus nucleic acids in this material was performed by reverse transcription polymerase chain reaction (RT-PCR).

RESULTS AND DISCUSSION

The overall prevalence of antibodies (Abs) among all monkeys was low and amounted 11.3% (95% CI: 9.2-13.7%, n = 811) for measles virus, 8.9% (95% CI: 6.2-12.2%, n = 381) for PI type 3 virus, 2.5% (95% CI: 0.8-5.6%, n = 204) for PI type 1 virus, and 7.7% (95% CI: 3.8-13.7%, n = 130) for adenoviruses. When testing 26 autopsy lung samples from monkeys of different species that died from pneumonia, 2 samples from Anubis baboons (Papio аnubis) were positive for of parainfluenza virus type 3 RNA.

CONCLUSION

Our data suggest the importance of the strict adherence to the terms of quarantine and mandatory testing of monkey sera for the presence of IgM antibodies to the measles virus that indicate the recent infection. The role of PI virus type 3 in the pathology of the respiratory tract in Anubis baboons has been established.

Effects of transdermal mirtazapine on hyporexic rhesus and cynomolgus macaques (Macaca mulatta and Macaca fascicularis)

BACKGROUND

Hyporexia and weight loss are important indicators of physical and psychological well-being in macaque colonies. An FDA-approved transdermal formulated Mirtazapine (MTZ) shows effectiveness in managing feline hyporexia. This study sought to determine its effectiveness as an appetite stimulant in macaques.

METHODS

Fourteen macaques with idiopathic hyporexia, intractable to conventional management were treated with transdermal MTZ (0.5 mg/kg) topically administered to aural pinnae once daily for 14 days. Qualitative food consumption was monitored daily for 6 months. Body weights were collected prior to treatment, every 2 weeks for the first 6 weeks, 10 weeks, and 6 months post-treatment.

RESULTS

Transdermal MTZ significantly reduced the frequency of hyporexia during treatment and monthly for 6 months. No significant increase in weight noted until approximately 6 months post-treatment.

CONCLUSIONS

Results from this study indicate that a short course of transdermal MTZ is an effective way to increase food consumption in macaques chronically.

Measles Encephalitis: Towards New Therapeutics

Measles remains a major cause of morbidity and mortality worldwide among vaccine preventable diseases. Recent decline in vaccination coverage resulted in re-emergence of measles outbreaks. Measles virus (MeV) infection causes an acute systemic disease, associated in certain cases with central nervous system (CNS) infection leading to lethal neurological disease. Early following MeV infection some patients develop acute post-infectious measles encephalitis (APME), which is not associated with direct infection of the brain. MeV can also infect the CNS and cause sub-acute sclerosing panencephalitis (SSPE) in immunocompetent people or measles inclusion-body encephalitis (MIBE) in immunocompromised patients. To date, cellular and molecular mechanisms governing CNS invasion are still poorly understood. Moreover, the known MeV entry receptors are not expressed in the CNS and how MeV enters and spreads in the brain is not fully understood. Different antiviral treatments have been tested and validated in vitro, ex vivo and in vivo, mainly in small animal models. Most treatments have high efficacy at preventing infection but their effectiveness after CNS manifestations remains to be evaluated. This review describes MeV neural infection and current most advanced therapeutic approaches potentially applicable to treat MeV CNS infection.

Modified Dose Efficacy Trial of a Canine Distemper-Measles Vaccine for Use in Rhesus Macaques (Macaca mulatta)

Measles virus causes a highly infectious disease in NHP. Clinical signs range from asymptomatic to fatal, although measles virus is most well-known for its characteristic generalized maculopapular rash. Along with appropriate quarantine practices, restricted human access, and appropriate personal protective equipment, vaccines are used to combat the risk of infection. The canine distemper-measles vaccine (CDMV), administered at the manufacturer's standard dose (1.0 mL IM), has been shown to be effective against clinical measles disease in rhesus macaques (Macaca mulatta). The goal of the current study was to test whether doses smaller than the manufacturer's recommended dose stimulated adequate antibody production to protect against infection. We hypothesized that either 0.25 or 0.5 mL IM of CDMV would stimulate antibody production comparable to the manufacturer's recommended dose. We found that the 0.25-mL dose was less effective at inducing antibodies than either the standard (1.0 mL) or 0.5-mL dose, which both yielded similar titers. The primary implication of this study informs balancing resource allocation and providing efficacious immunity. By using half the manufacturer-recommended dose, the 50% cost reduction may provide sufficient monetary incentive to implement, maintain, or modify measles vaccination programs at NHP facilities.

Seroprevalence of viral infections in captive rhesus and cynomolgus macaques

Macaques serve as important animal models for biomedical research. Viral infection of macaques can compromise animal health as well as the results of biomedical research, and infected animals constitute an occupational health risk. Therefore, monitoring macaque colonies for viral infection is an important task. We used a commercial chip-based assay to analyze sera of 231 macaques for the presence of antibody responses against nine animal and human viruses. We report high seroprevalence of cytomegalovirus (CMV), lymphocryptovirus (LCV), rhesus rhadinovirus (RRV) and simian foamy virus (SFV) antibodies in all age groups. In contrast, antibodies against simian retrovirus type D (SRV/D) and simian T cell leukemia virus (STLV) were detected only in 5 % and 10 % of animals, respectively, and were only found in adult or aged animals. Moreover, none of the animals had antibodies against herpes B virus (BV), in keeping with the results of in-house tests previously used for screening. Finally, an increased seroprevalence of measles virus antibodies in animals with extensive exposure to multiple humans for extended periods of time was observed. However, most of these animals were obtained from external sources, and a lack of information on the measles antibody status of the animals at the time of arrival precluded drawing reliable conclusions from the data. In sum, we show, that in the colony studied, CMV, LCV, RRV and SFV infection was ubiquitous and likely acquired early in life while SRV/D and STLV infection was rare and likely acquired during adulthood.

Recommended Diagnostic Approach to Documenting and Reporting Skin Findings of Nonhuman Primates from Regulatory Toxicity Studies

Cutaneous adverse drug reactions (CADRs) in patients are not uncommon, and they are difficult to predict from nonclinical safety studies. Nonhuman primates (NHPs) are predestinated for a high predictivity of adverse drug reactions, and we postulate that this may also be true for CADRs, if skin findings in NHPs are thoroughly worked up, following the diagnostic approach in clinical veterinary dermatology. This article proposes a systematic approach to describe, analyze, and report skin findings that occur in NHP toxicity studies. Implementing this approach may increase the likelihood to differentiate between test item–related cutaneous findings and those that are independent of the test item. This will eventually result in increased relevance of skin findings identified in the scope of an NHP regulatory toxicity study for the risk assessment process to safeguard patients in clinical trials and beyond.

Non-invasive surveillance for Plasmodium in reservoir macaque species

BACKGROUND

Primates are important reservoirs for human diseases, but their infection status and disease dynamics are difficult to track in the wild. Within the last decade, a macaque malaria, Plasmodium knowlesi, has caused disease in hundreds of humans in Southeast Asia. In order to track cases and understand zoonotic risk, it is imperative to be able to quantify infection status in reservoir macaque species. In this study, protocols for the collection of non-invasive samples and isolation of malaria parasites from naturally infected macaques are optimized.

METHODS

Paired faecal and blood samples from 60 Macaca fascicularis and four Macaca nemestrina were collected. All animals came from Sumatra or Java and were housed in semi-captive breeding colonies around West Java. DNA was extracted from samples using a modified protocol. Nested polymerase chain reactions (PCR) were run to detect Plasmodium using primers targeting mitochondrial DNA. Sensitivity of screening faecal samples for Plasmodium was compared to other studies using Kruskal Wallis tests and logistic regression models.

RESULTS

The best primer set was 96.7 % (95 % confidence intervals (CI): 83.3-99.4 %) sensitive for detecting Plasmodium in faecal samples of naturally infected macaques (n = 30). This is the first study to produce definitive estimates of Plasmodium sensitivity and specificity in faecal samples from naturally infected hosts. The sensitivity was significantly higher than some other studies involving wild primates.

CONCLUSIONS

Faecal samples can be used for detection of malaria infection in field surveys of macaques, even when there are no parasites visible in thin blood smears. Repeating samples from individuals will improve inferences of the epidemiology of malaria in wild primates.

Molecular Localization Techniques in the Diagnosis and Characterization of Nonhuman Primate Infectious Diseases

Molecular localization techniques remain important diagnostic and research tools for the pathologist evaluating nonhuman primate tissues. In situ hybridization and immunohistochemistry protocols have been developed for many important pathogens of nonhuman primates, including RNA and DNA viruses, prions, and bacterial, protozoal, and fungal pathogens. Such techniques will remain critical in defining the impact and relevance of novel agents on animal health and disease. A comparative pathology perspective often provides valuable insight to the best strategy for reagent development and can also facilitate interpretation of molecular localization patterns. Such a perspective is grounded in a firm understanding of microbe-host pathobiology. This review summarizes current molecular localization protocols used in the diagnosis of selected primate infectious diseases.

Immunogenicity of a recombinant measles HIV-1 subtype C vaccine

The HIV epidemic is greatest in Sub-Saharan Africa and India where HIV-1 subtype C is predominant. To control the spread of HIV in these parts of the world a preventive HIV-1 subtype C vaccine is urgently required. Here we report the immunogenicity of a candidate HIV-1 subtype C vaccine delivered by a recombinant measles vector carrying an insert encoding HIV-1 subtype C Gag, RT and Nef (MV1-F4), in MHC-typed non-human primates. HIV-1 specific cytokine secreting CD4+ and CD8+ T cell responses were detected in 15 out of 16 vaccinees. These HIV-specific T cell responses persisted in lymphoid tissues. Anti-HIV-1 antibody responses were detected in 15 out of 16 vaccinees and titres were boosted by a second immunisation carried out 84 days later. These findings support further exploration of the MV1-F4 vector as a candidate HIV-1 subtype C vaccine or as part of a wider vaccine strategy.

Infection of lymphoid tissues in the macaque upper respiratory tract contributes to the emergence of transmissible measles virus

Measles virus (MV), a member of the family Paramyxoviridae, remains a major cause of morbidity and mortality in the developing world. MV is spread by aerosols but the mechanism(s) responsible for the high transmissibility of MV are largely unknown. We previously infected macaques with enhanced green fluorescent protein-expressing recombinant MV and euthanized them at a range of time points. In this study a comprehensive pathological analysis has been performed of tissues from the respiratory tract around the peak of virus replication. Isolation of virus from nose and throat swab samples showed that high levels of both cell-associated and cell-free virus were present in the upper respiratory tract. Analysis of tissue sections from lung and primary bronchus revealed localized infection of epithelial cells, concomitant infiltration of MV-infected immune cells into the epithelium and localized shedding of cells or cell debris into the lumen. While high numbers of MV-infected cells were present in the tongue, these were largely encapsulated by intact keratinocyte cell layers that likely limit virus transmission. In contrast, the integrity of tonsillar and adenoidal epithelia was disrupted with high numbers of MV-infected epithelial cells and infiltrating immune cells present throughout epithelial cell layers. Disruption was associated with large numbers of MV-infected cells or cell debris ‘spilling’ from epithelia into the respiratory tract. The coughing and sneezing response induced by disruption of the ciliated epithelium, leading to the expulsion of MV-infected cells, cell debris and cell-free virus, contributes to the highly infectious nature of MV.

Immunogenicity of a recombinant measles-HIV-1 clade B candidate vaccine

Live attenuated measles virus is one of the most efficient and safest vaccines available, making it an attractive candidate vector for a HIV/AIDS vaccine aimed at eliciting cell-mediated immune responses (CMI). Here we have characterized the potency of CMI responses generated in mice and non-human primates after intramuscular immunisation with a candidate recombinant measles vaccine carrying an HIV-1 insert encoding Clade B Gag, RT and Nef (MV1-F4). Eight Mauritian derived, MHC-typed cynomolgus macaques were immunised with 10⁵ TCID₅₀ of MV1-F4, four of which were boosted 28 days later with the same vaccine. F4 and measles virus (MV)-specific cytokine producing T cell responses were detected in 6 and 7 out of 8 vaccinees, respectively. Vaccinees with either M6 or recombinant MHC haplotypes demonstrated the strongest cytokine responses to F4 peptides. Polyfunctional analysis revealed a pattern of TNFα and IL-2 responses by CD4+ T cells and TNFα and IFNγ responses by CD8+ T cells to F4 peptides. HIV-specific CD4+ and CD8+ T cells expressing cytokines waned in peripheral blood lymphocytes by day 84, but CD8+ T cell responses to F4 peptides could still be detected in lymphoid tissues more than 3 months after vaccination. Anti-F4 and anti-MV antibody responses were detected in 6 and 8 out of 8 vaccinees, respectively. Titres of anti-F4 and MV antibodies were boosted in vaccinees that received a second immunisation. MV1-F4 carrying HIV-1 Clade B inserts induces robust boostable immunity in non-human primates. These results support further exploration of the MV1-F4 vector modality in vaccination strategies that may limit HIV-1 infectivity.

Zoonotic diseases of primates

A zoonotic disease is transmissible from vertebrate animals to humans. This article focuses on pertinent zoonotic diseases that have to be taken into consideration when working with nonhuman primate (NHP) species. Many factors may influence the occurrence of these diseases. Human and NHPs share many similarities, not only anatomically but also physiologically. NHP are valuable models for many human infectious diseases; therefore, staff can be exposed to many potential pathogens. In general, the disease state of a primate can range from asymptomatic carrier to death from infection.

Emerging and reemerging infectious diseases of nonhuman primates in the laboratory setting

Despite numerous advances in the diagnosis and control of infectious diseases of nonhuman primates in the laboratory setting, a number of infectious agents continue to plague colonies. Some, such as measles virus and Mycobacterium tuberculosis, cause sporadic outbreaks despite well-established biosecurity protocols, whereas others, such as retroperitoneal fibromatosis-associated herpesvirus, have only recently been discovered, often as a result of immunosuppressive experimental manipulation. Owing to the unique social housing requirements of nonhuman primates, importation of foreign-bred animals, and lack of antemortem diagnostic assays for many new diseases, elimination of these agents is often difficult or impractical. Recognition of these diseases is therefore essential because of their confounding effects on experimental data, impact on colony health, and potential for zoonotic transmission. This review summarizes the relevant pathology and pathogenesis of emerging and reemerging infectious diseases of laboratory nonhuman primates.

Overview of known non-human primate pathogens with potential to affect colonies used for toxicity testing

The increased demand for non-human primates (NHPs) in biomedical research has resulted in alternative sources of animals being used, which has allowed for importation of animals with varying background incidences of bacterial, viral, parasitic, and fungal pathogens. This can be of minimal consequence when animals from different sources are kept isolated. However, when NHPs from different sources with varying incidences of primary and opportunistic pathogens are mixed, there can be a rapid spread of these pathogens and an increase in the seroconversion of susceptible animals. If this process occurs during the conduct of a study, interpretation of that study can be confounded. Furthermore, NHPs imported from areas enzootic for pathogens such as Plasmodium or with high incidences of human diseases such as measles and tuberculosis can introduce diseases that can be a threat to colony health, have zoonotic risk, and can severely impact study outcome. Thus, knowledge of the common primary and opportunistic NHP infections, as well as reemerging pathogens, enables the toxicologist to use information on disease status for pre-study animal selection and intelligent study design. This is particularly important when immunomodulatory compounds are being investigated. Moreover, the toxicologic pathologist well versed in the common spontaneous infections, opportunistic pathogens, and background lesions in NHPs is able to assess possible drug-related effects in drug safety studies. This review identifies the common primary and opportunistic pathogens, as well as newly emerging infections of NHPs, that can directly or indirectly affect colony health and the interpretation of drug safety studies.

The significant but understudied impact of pathogen transmission from humans to animals

Zooanthroponotic pathogens, which are transmitted from humans to nonhuman animals, are an understudied aspect of global health, despite their potential to cause significant disease burden in wild and domestic animal populations and affect global economies. Some key human-borne pathogens that have been shown to infect animals and cause morbidity and mortality include measles virus (paramyxoviruses), influenza A virus (orthomyxoviruses), herpes simplex 1 virus (herpesviruses), protozoal and helminthic parasites, and bacteria such as methicillin-resistant Staphylococcus aureus and Mycobacterium tuberculosis. However, zooanthroponotic pathogens are most commonly reported in captive animals or domestic livestock with close human contact; there, the potential for economic loss and human reinfection is most apparent. There is also the potential for infection in wild animal populations, which may threaten endangered species and decrease biodiversity. The emergence and reemergence of human-borne pathogens in wildlife may also have negative consequences for human health if these pathogens cycle back into humans. Many of the anthropogenic drivers of zoonotic disease emergence also facilitate zooanthroponotic transmission. Increasing research to better understand the occurrence of and the potential for bidirectional pathogen transmission between humans and animals is essential for improving global health. Mt Sinai J Med 76:448-455, 2009. (c) 2009 Mount Sinai School of Medicine.

Macaque models of human infectious disease

Macaques have served as models for more than 70 human infectious diseases of diverse etiologies, including a multitude of agents—bacteria, viruses, fungi, parasites, prions. The remarkable diversity of human infectious diseases that have been modeled in the macaque includes global, childhood, and tropical diseases as well as newly emergent, sexually transmitted, oncogenic, degenerative neurologic, potential bioterrorism, and miscellaneous other diseases. Historically, macaques played a major role in establishing the etiology of yellow fever, polio, and prion diseases. With rare exceptions (Chagas disease, bartonellosis), all of the infectious diseases in this review are of Old World origin. Perhaps most surprising is the large number of tropical (16), newly emergent (7), and bioterrorism diseases (9) that have been modeled in macaques. Many of these human diseases (e.g., AIDS, hepatitis E, bartonellosis) are a consequence of zoonotic infection. However, infectious agents of certain diseases, including measles and tuberculosis, can sometimes go both ways, and thus several human pathogens are threats to nonhuman primates including macaques. Through experimental studies in macaques, researchers have gained insight into pathogenic mechanisms and novel treatment and vaccine approaches for many human infectious diseases, most notably acquired immunodeficiency syndrome (AIDS), which is caused by infection with human immunodeficiency virus (HIV). Other infectious agents for which macaques have been a uniquely valuable resource for biomedical research, and particularly vaccinology, include influenza virus, paramyxoviruses, flaviviruses, arenaviruses, hepatitis E virus, papillomavirus, smallpox virus, Mycobacteria, Bacillus anthracis, Helicobacter pylori, Yersinia pestis, and Plasmodium species. This review summarizes the extensive past and present research on macaque models of human infectious disease.

Impact of infections and normal flora in nonhuman primates on drug development

Preclinical safety studies that are required for the marketing approval of a pharmaceutical include single and repeat dose studies in rodent and nonrodent species. The use of nonhuman primates (NHPs), primarily macaques, as the nonrodent species has increased in recent years, in part due to the increase in development of biopharmaceuticals and immunomodulatory agents. Depending on the source of the macaques, they may vary in genetic background, normal flora, and/or the incidence of preexisting pathogens and inflammatory conditions. As the use of alternative sources of macaques rises to meet the increased demand for these animals in biomedical research, the toxicologic pathologist should be well versed in NHP pathology to adequately assess potential drug-related effects in the context of these variations. Such knowledge is particularly important in studies involving immunomodulatory drugs as the toxicologic pathologist should anticipate which type(s) of infections are most likely to arise depending on which arm of the immune system is modulated. The purpose of this review is to discuss the immunosuppressive (e.g., simian type D retrovirus, simian immunodeficiency virus) and opportunistic viruses (e.g., cytomegalovirus, adenovirus, simian virus 40, rhesus rhadinovirus, and lymphocryptovirus), primary and opportunistic bacteria (e.g., Campylobacter spp., Shigella flexneri, Yersinia enterocolitica, Moraxella catarrhalis, Mycobacterium avium complex, enteropathogenic Escherichia coli), and parasites (e.g., Plasmodium spp., Schistosoma spp., Strongyloides fulleborni) that have had the most profound impact on the interpretation of drug safety studies and/or that may reemerge as alternative sources of NHPs are used for drug safety studies.

Retrospective evaluation of measles antibody titers in vaccinated captive gorillas (Gorilla gorilla gorilla)

Retrospective analyses of banked serum samples and medical records from captive western lowland gorillas (Gorilla gorilla gorilla) at Lincoln Park Zoo showed that vaccination of gorillas with a human vaccine induced antibody production. No significant relationship was found between the groups that received one, two, or three vaccinations and the probability of seroconversion. These data also suggested that antibodies in western lowland gorillas persist for at least 11 yr. This information is useful in the assessment of vaccination protocols for captive gorillas and in the implementation of preventive care in wild gorilla populations.

Gingival and other oral manifestations in measles virus infection

BACKGROUND

Measles is a highly contagious, viral infectious disease affecting mainly children and young adults. It is characterized by high fever, maculopapular rash, keratoconjunctivitis and pathognomonic oral Koplik's spots.

METHODS

During an outbreak of measles among soldiers in the Israeli military, patients were referred to one medical center where they were also examined for oral signs and symptoms of their illness.

RESULTS

We present a case of measles infection with distinct oral findings. These included Koplik's spots, various forms of ulcerations of the free mucosa, -like gingivitis and pericoronitis. All oral lesions resolved after cessation of systemic illness.

CONCLUSIONS

The measles virus is associated with a transient inhibition of the host response. Immunosuppression may create the necessary condition for the proliferation of pathobacteria associated with the observed pericoronitis and the other gingival lesions.

Reduced efficacy of hemorrhagic enteritis virus vaccine in turkeys exposed to avian pneumovirus

Avian pneumovirus (APV) is an immunosuppressive respiratory pathogen of turkeys. We examined the effect of APV infection on the vaccine efficacy of hemorrhagic enteritis virus (HEV) vaccines. APV was inoculated in 2-wk-old turkeys. Two or four days later, an attenuated HEV vaccine (HEVp30) or marble spleen disease virus (MSDV) vaccine were administered. Virulent HEV challenge was given 19 days after HEV vaccination. APV exposure compromised the ability of HEVp30 and MSDV to protect turkeys against virulent HEV. The protective index values were as follows: MSDV (100%) versus APV + MSDV (0%) (P < 0.05); HEVp30 (60%) versus APV + HEVp30 (30%) (P < 0.05) (Experiment I) and HEVp30 (56%) versus APV + HEVp30 (20%) (P < 0.05) (Experiment II). These data indicated that APV reduced the efficacy of HEV vaccines in turkeys.

Pathogenic and immunosuppressive effects of avian pneumovirus in turkeys

Avian pneumovirus (APV) causes a respiratory disease in turkeys. The virus has been associated with morbidity and mortality due to secondary infections. Our objective was to determine if APV caused immunosuppression in the T-cell or B-cell compartments and to study the pathogenesis of the disease in APV maternal antibody-lacking 2-wk-old commercial turkeys. APV was administered by the eyedrop/intranasal route. Observations were made for gross lesions, viral genome, and T-cell mitogenesis and cytokine secretion at 3, 5, 7, 14, and 21 days postinoculation (DPI). During the acute phase of the disease that lasted for about 1 wk, the turkeys exposed to APV showed clinical signs characterized by nasal discharge and sinus swelling. Virus genome was detected by in situ hybridization in cells of turbinates and trachea at 3 and 5 DPI. At 3 and 5 DPI, spleen cells of the birds infected with APV markedly decreased proliferative response to concanavalin A (Con A). Con A and lipopolysaccharide stimulation of spleen cells from virus-exposed turkeys resulted in accumulation of nitric oxide-inducing factors (NOIF) in the culture fluid. NOIF were not detected in culture fluids of Con A-stimulated spleen cells of virus-free turkeys. APV did not compromise the antibody-producing ability of turkeys against several extraneous antigens such as Brucella abortus and tetanus toxoid.