Smallpox lesion characterization in placebo-treated and tecovirimat-treated macaques using traditional and novel methods

Smallpox was the most rampant infectious disease killer of the 20th century, yet much remains unknown about the pathogenesis of the variola virus. Using archived tissue from a study conducted at the Centers for Disease Control and Prevention we characterized pathology in 18 cynomolgus macaques intravenously infected with the Harper strain of variola virus. Six macaques were placebo-treated controls, six were tecovirimat-treated beginning at 2 days post-infection, and six were tecovirimat-treated beginning at 4 days post-infection. All macaques were treated daily until day 17. Archived tissues were interrogated using immunohistochemistry, in situ hybridization, immunofluorescence, and electron microscopy. Gross lesions in three placebo-treated animals that succumbed to infection primarily consisted of cutaneous vesicles, pustules, or crusts with lymphadenopathy. The only gross lesions noted at the conclusion of the study in the three surviving placebo-treated and the Day 4 treated animals consisted of resolving cutaneous pox lesions. No gross lesions attributable to poxviral infection were present in the Day 2 treated macaques. Histologic lesions in three placebo-treated macaques that succumbed to infection consisted of proliferative and necrotizing dermatitis with intracytoplasmic inclusion bodies and lymphoid depletion. The only notable histologic lesion in the Day 4 treated macaques was resolving dermatitis; no notable lesions were seen in the Day 2 treated macaques. Variola virus was detected in all three placebo-treated animals that succumbed to infection prior to the study's conclusion by all utilized methods (IHC, ISH, IFA, EM). None of the three placebo-treated animals that survived to the end of the study nor the animals in the two tecovirimat treatment groups showed evidence of variola virus by these methods. Our findings further characterize variola lesions in the macaque model and describe new molecular methods for variola detection.

Temporal changes in pathology and viral RNA distribution in guinea pigs following separate infection with two New World Arenaviruses

Numerous arenaviruses have been identified throughout the Americas and a subset of these viruses cause viral hemorrhagic fever in humans. This study compared the pathology and viral RNA distribution in Hartley guinea pigs challenged with two human-disease causing New World arenaviruses, Junin virus (JUNV) or Guanarito virus (GTOV). Histopathologic analysis and RNA in situ hybridization revealed similar pathology and viral RNA distribution for both groups of animals challenged with either JUNV or GTOV on days 3, 7, 10 and 12 post exposure (PE). Gross lesions were first observed on day 7 and primarily involved the lungs and liver. The most severe histologic lesions occurred in the lymph nodes, spleen, and thymus and included lymphoid depletion and necrosis which increased in severity over time. Extensive necrosis was also observed in the bone marrow on day 12. Minimal to mild inflammation with and without necrosis was observed in the choroid plexus of the brain, choroid of the eye, intestinal tract, lung and adrenal gland. Significant liver lesions were rare, consisting predominantly of hepatocyte vacuolation. Viral RNA labeling was identified in nearly all organs examined, was often extensive in certain organs and generally increased over time starting on day 7. Our data demonstrate the guinea pig may serve as a useful model to study New World arenavirus infection in humans and for the evaluation and development of medical countermeasures.

Retrospective detection of monkeypox virus in the testes of nonhuman primate survivors

Close contact through sexual activity has been associated with the spread of monkeypox virus (MPXV) in the ongoing, global 2022 epidemic. However, it remains unclear whether MPXV replicates in the testes or is transmitted via semen to produce an active infection. We carried out a retrospective analysis of MPXV-infected crab-eating macaque archival tissue samples from acute and convalescent phases of infection of clade I or clade II MPXV using immunostaining and RNA in situ hybridization. We detected MPXV in interstitial cells and seminiferous tubules of testes as well as epididymal lumina, which are the sites of sperm production and maturation. We also detected inflammation and necrosis during the acute phase of the disease by histological analysis. Finally, we found that MPXV was cleared from most organs during convalescence, including healed skin lesions, but could be detected for up to 37 d post-exposure in the testes of convalescent macaques. Our findings highlight the potential for sexual transmission of MPXV in humans.

Evaluation of Virulence in Cynomolgus Macaques Using a Virus Preparation Enriched for the Extracellular Form of Monkeypox Virus

The 2022 global human monkeypox outbreak emphasizes the importance of maintaining poxvirus research, including enriching a basic understanding of animal models for developing and advancing therapeutics and vaccines. Intravenous administration of monkeypox virus in macaques is arguably one of the best animal models for evaluating the efficacy of medical countermeasures. Here we addressed one criticism of the model, a requirement for a high-titer administration of virus, as well as improving our understanding of monkeypox virus pathogenesis. To do so, we infected macaques with a challenge dose containing a characterized inoculum enriched for the extracellular form of monkeypox virus. Although there were some differences between diseases caused by the enriched preparation compared with a relatively similar unpurified preparation, we were unable to reduce the viral input with the enriched preparation and maintain severe disease. We found that inherent factors contained within the serum of nonhuman primate blood affect the stability of the monkeypox extracellular virions. As a first step to study a role of the extracellular form in transmission, we also showed the presence of this form in the oropharyngeal swabs from nonhuman primates exposed to monkeypox virus.

Detailed analysis of the pathologic hallmarks of Nipah virus (Malaysia) disease in the African green monkey infected by the intratracheal route

Disease associated with Nipah virus infection causes a devastating and often fatal spectrum of syndromes predominated by both respiratory and neurologic conditions. Additionally, neurologic sequelae may manifest months to years later after virus exposure or apparent recovery. In the two decades since this disease emerged, much work has been completed in an attempt to understand the pathogenesis and facilitate development of medical countermeasures. Here we provide detailed organ system-specific pathologic findings following exposure of four African green monkeys to 2.41×105 pfu of the Malaysian strain of Nipah virus. Our results further substantiate the African green monkey as a model of human Nipah virus disease, by demonstrating both the respiratory and neurologic components of disease. Additionally, we demonstrate that a chronic phase of disease exists in this model, that may provide an important opportunity to study the enigmatic late onset and relapse encephalitis as it is described in human disease.

Nipah virus persists in the brains of nonhuman primate survivors

Nipah virus (NiV) is an emerging zoonotic paramyxovirus that causes highly lethal henipavirus encephalitis in humans. Survivors develop various neurologic sequelae, including late-onset and relapsing encephalitis, several months up to several years following initial infection. However, the underlying pathology and disease mechanisms of persistent neurologic complications remain unknown. Here, we demonstrate persistent NiV infection in the brains of grivets that survived experimental exposure to NiV. Encephalitis affected the entire brains, with the majority of NiV detected in the neurons and microglia of the brainstems, cerebral cortices, and cerebella. We identified the vascular endothelium in the brain as an initial target of NiV infection during the acute phase of disease, indicating a primary path of entry for NiV into the brain. Notably, we were unable to detect NiV anywhere else except the brains in the examined survivors. Our findings indicate that late-onset and relapsing encephalitis of NiV in human survivors may be due to viral persistence in the brain and shed light on the pathogenesis of chronic henipavirus encephalitis.

Maternal and child health after injuries: a two-year follow-up of a nationally representative sample

OBJECTIVE

The objective of this study was to examine the association between childhood injury and health outcomes among survivors and their mothers using a national survey in the United States (US).

STUDY DESIGN

This was a longitudinal analysis of a nationally representative sample.

METHODS

Secondary analysis of the 1997-2013 Medical Expenditure Panel Survey (MEPS) was performed. Children (aged 2-18 years) with or without injuries were followed up for two years. Injuries captured in the study were those associated with at least one hospitalization, emergency department visit, or office-based visit. Outcome measures were child and maternal general and mental health status. Multiple mixed-logistic regressions were used with suboptimal health defined as the response of poor or fair health versus good, very good, or excellent health.

RESULTS

Of the 63,422 children analyzed, 3251 (4.9%) were injured, representing 3.6 million US children. Injured children were more likely to be male, white, and older than those without injuries (P < 0.01). About a fifth of injured children suffered head injuries. Injuries were strongly associated with suboptimal general and mental health status in children (adjusted odds ratios [AORs], 1.35 and 1.36, respectively, P < 0.05). Mothers of children with injuries were also more likely to report suboptimal mental health (AOR, 1.30, P < 0.05).

CONCLUSION

Injuries among children are associated with lasting adverse effects in general and mental health. To improve health outcomes of pediatric injuries, further follow-up care may be needed to ensure that they return to pre-injury health levels. These results highlight the importance of primary prevention and the long-term impact of injuries on the health of children and their mothers.

Combination Kinase Inhibitor Treatment Suppresses Rift Valley Fever Virus Replication

Viruses must parasitize host cell translational machinery in order to make proteins for viral progeny. In this study, we sought to use this signal transduction conduit against them by inhibiting multiple kinases that influence translation. Previous work indicated that several kinases involved in translation, including p70 S6K, p90RSK, ERK, and p38 MAPK, are phosphorylated following Rift Valley fever virus (RVFV) infection. Furthermore, inhibiting p70 S6K through treatment with the FDA approved drug rapamycin prevents RVFV pathogenesis in a mouse model of infection. We hypothesized that inhibiting either p70 S6K, p90RSK, or p90RSK’s upstream kinases, ERK and p38 MAPK, would decrease translation and subsequent viral replication. Treatment with the p70 S6K inhibitor PF-4708671 resulted in decreased phosphorylation of translational proteins and reduced RVFV titers. In contrast, treatment with the p90RSK inhibitor BI-D1870, p38MAPK inhibitor SB203580, or the ERK inhibitor PD0325901 alone had minimal influence on RVFV titers. The combination of PF-4708671 and BI-D1870 treatment resulted in robust inhibition of RVFV replication. Likewise, a synergistic inhibition of RVFV replication was observed with p38MAPK inhibitor SB203580 or the ERK inhibitor PD0325901 combined with rapamycin treatment. These findings serve as a proof of concept regarding combination kinase inhibitor treatment for RVFV infection.

A DNA vaccine delivered by dermal electroporation fully protects cynomolgus macaques against Lassa fever

Lassa virus (LASV) is an ambisense RNA virus in the Arenaviridae family and is the etiological agent of Lassa fever, a severe hemorrhagic disease endemic to West and Central Africa.^1,2 There are no US Food and Drug Administration (FDA)-licensed vaccines available to prevent Lassa fever.^1,2 in our previous studies, we developed a gene-optimized DNA vaccine that encodes the glycoprotein precursor gene of LASV (Josiah strain) and demonstrated that 3 vaccinations accompanied by dermal electroporation protected guinea pigs from LASV-associated illness and death. Here, we describe an initial efficacy experiment in cynomolgus macaque nonhuman primates (NHPs) in which we followed an identical 3-dose vaccine schedule that was successful in guinea pigs, and a follow-on experiment in which we used an accelerated vaccination strategy consisting of 2 administrations, spaced 4 weeks apart. In both studies, all of the LASV DNA-vaccinated NHPs survived challenge and none of them had measureable, sustained viremia or displayed weight loss or other disease signs post-exposure. Three of 10 mock-vaccinates survived exposure to LASV, but all of them became acutely ill post-exposure and remained chronically ill to the study end point (45 d post-exposure). Two of the 3 survivors experienced sensorineural hearing loss (described elsewhere). These results clearly demonstrate that the LASV DNA vaccine combined with dermal electroporation is a highly effective candidate for eventual use in humans.

C-Peptide replacement therapy in type 1 diabetes: are we in the trough of disillusionment?

Type 1 diabetes is associated with such complications as blindness, kidney failure, and nerve damage. Replacing C-peptide, a hormone normally co-secreted with insulin, has been shown to reduce diabetes-related complications. Interestingly, after nearly 30 years of positive research results, C-peptide is still not being co-administered with insulin to diabetic patients. The following review discusses the potential of C-peptide as an auxilliary replacement therapy and why it's not currently being used as a therapeutic.

Rapamycin modulation of p70 S6 kinase signaling inhibits Rift Valley fever virus pathogenesis

Despite over 60 years of research on antiviral drugs, very few are FDA approved to treat acute viral infections. Rift Valley fever virus (RVFV), an arthropod borne virus that causes hemorrhagic fever in severe cases, currently lacks effective treatments. Existing as obligate intracellular parasites, viruses have evolved to manipulate host cell signaling pathways to meet their replication needs. Specifically, translation modulation is often necessary for viruses to establish infection in their host. Here we demonstrated phosphorylation of p70 S6 kinase, S6 ribosomal protein, and eIF4G following RVFV infection in vitro through western blot analysis and in a mouse model of infection through reverse phase protein microarrays (RPPA). Inhibition of p70 S6 kinase through rapamycin treatment reduced viral titers in vitro and increased survival and mitigated clinical disease in RVFV challenged mice. Additionally, the phosphorylation of p70 S6 kinase was decreased following rapamycin treatment in vivo. Collectively these data demonstrate modulating p70 S6 kinase can be an effective antiviral strategy.

Temporal Progression of Lesions in Guinea Pigs Infected With Lassa Virus

Lassa virus (LASV) infection causes an acute, multisystemic viral hemorrhagic fever that annually infects an estimated 100 000 to 300 000 persons in West Africa. This pathogenesis study evaluated the temporal progression of disease in guinea pigs following aerosol and subcutaneous inoculation of the Josiah strain of LASV as well as the usefulness of Strain 13 guinea pigs as an animal model for Lassa fever. After experimental infection, guinea pigs ( Cavia porcellus; n = 67) were serially sampled to evaluate the temporal progression of infection, gross and histologic lesions, and serum chemistry and hematologic changes. Guinea pigs developed viremia on day 5 to 6 postexposure (PE), with clinical signs appearing by day 7 to 8 PE. Complete blood counts revealed lymphopenia and thrombocytopenia. Gross pathologic findings included skin lesions and congested lungs. Histologic lesions consisted of cortical lymphoid depletion by day 6 to 7 PE with lymphohistiocytic interstitial pneumonia at 7 to 8 days PE. Scattered hepatocellular degeneration and cell death were also noted in the liver and, to a lesser extent, in other tissues including the haired skin, lung, heart, adrenal gland, lymph nodes, thymus, and spleen. The first cell types to demonstrate staining for viral antigen were fibroblastic reticular cells and macrophages/dendritic cells in the lymph nodes on day 5 to 6 PE. This study demonstrates similarities between Lassa viral disease in human infections and experimental guinea pig infection. These shared pathologic characteristics support the utility of guinea pigs as an additional animal model for vaccine and therapeutic development under the Food and Drug Administration's Animal Rule.

Pathogenesis of Bolivian Hemorrhagic Fever in Guinea Pigs

Machupo virus, the cause of Bolivian hemorrhagic fever, is a highly lethal viral hemorrhagic fever with no Food and Drug Administration-approved vaccines or therapeutics. This study evaluated the guinea pig as a model using the Machupo virus-Chicava strain administered via aerosol challenge. Guinea pigs (Cavia porcellus) were serially sampled to evaluate the temporal progression of infection, gross and histologic lesions, and sequential changes in serum chemistry and hematology. The incubation period was 5 to 12 days, and complete blood counts revealed leukopenia with lymphopenia and thrombocytopenia. Gross pathologic findings included congestion and hemorrhage of the gastrointestinal mucosa and serosa, noncollapsing lungs with fluid exudation, enlarged lymph nodes, and progressive pallor and friability of the liver. Histologic lesions consisted of foci of degeneration and cell death in the haired skin, liver, pancreas, adrenal glands, lymph nodes, tongue, esophagus, salivary glands, renal pelvis, small intestine, and large intestine. Lymphohistiocytic interstitial pneumonia was also present. Inflammation within the central nervous system, interpreted as nonsuppurative encephalitis, was histologically apparent approximately 16 days postexposure and was generally progressive. Macrophages in the tracheobronchial lymph node, on day 5 postexposure, were the first cells to demonstrate visible viral antigen. Viral antigen was detected throughout the lymphoid system by day 9 postexposure, followed by prominent spread within epithelial tissues and then brain. This study provides insight into the course of Machupo virus infection and supports the utility of guinea pigs as an additional animal model for vaccine and therapeutic development.

Serum biomarkers of Burkholderia mallei infection elucidated by proteomic imaging of skin and lung abscesses

Background

The bacterium Burkholderia mallei is the etiological agent of glanders, a highly contagious, often fatal zoonotic infectious disease that is also a biodefense concern. Clinical laboratory assays that analyze blood or other biological fluids are the highest priority because these specimens can be collected with minimal risk to the patient. However, progress in developing sensitive assays for monitoring B. mallei infection is hampered by a shortage of useful biomarkers.

Results

Reasoning that there should be a strong correlation between the proteomes of infected tissues and circulating serum, we employed imaging mass spectrometry (IMS) of thin-sectioned tissues from Chlorocebus aethiops (African green) monkeys infected with B. mallei to localize host and pathogen proteins that were associated with abscesses. Using laser-capture microdissection of specific regions identified by IMS and histology within the tissue sections, a more extensive proteomic analysis was performed by a technique that combined the physical separation capabilities of liquid chromatography (LC) with the sensitive mass analysis capabilities of mass spectrometry (LC-MS/MS). By examining standard formalin-fixed, paraffin-embedded tissue sections, this strategy resulted in the identification of several proteins that were associated with lung and skin abscesses, including the host protein calprotectin and the pathogen protein GroEL. Elevated levels of calprotectin detected by ELISA and antibody responses to GroEL, measured by a microarray of the bacterial proteome, were subsequently detected in the sera of C. aethiops, Macaca mulatta, and Macaca fascicularis primates infected with B. mallei.

Conclusions

Our results demonstrate that a combination of multidimensional MS analysis of traditional histology specimens with high-content protein microarrays can be used to discover lead pairs of host-pathogen biomarkers of infection that are identifiable in biological fluids.

Electronic supplementary material

The online version of this article (doi:10.1186/s12014-015-9079-4) contains supplementary material, which is available to authorized users.

Pathology of experimental Machupo virus infection, Chicava strain, in cynomolgus macaques (Macaca fascicularis) by intramuscular and aerosol exposure

Machupo virus, the causative agent of Bolivian hemorrhagic fever (BHF), is a highly lethal viral hemorrhagic fever of which little is known and for which no Food and Drug Administration-approved vaccines or therapeutics are available. This study evaluated the cynomolgus macaque as an animal model using the Machupo virus, Chicava strain, via intramuscular and aerosol challenge. The incubation period was 6 to 10 days with initial signs of depression, anorexia, diarrhea, mild fever, and a petechial skin rash. These were often followed by neurologic signs and death within an average of 18 days. Complete blood counts revealed leukopenia as well as marked thrombocytopenia. Serum chemistry values identified a decrease in total protein, marked increases in alanine aminotransferase and aspartate aminotransferase, and moderate increases in alkaline phosphatase. Gross pathology findings included a macular rash extending across the axillary and inguinal regions beginning at approximately 10 days postexposure as well as enlarged lymph nodes and spleen, enlarged and friable liver, and sporadic hemorrhages along the gastrointestinal mucosa and serosa. Histologic lesions consisted of foci of degeneration and necrosis/apoptosis in the haired skin, liver, pancreas, adrenal glands, lymph nodes, tongue, esophagus, salivary glands, stomach, small intestine, and large intestine. Lymphohistiocytic interstitial pneumonia was also present. Inflammation within the central nervous system (nonsuppurative encephalitis) was histologically apparent approximately 16 days postexposure and was generally progressive. This study provides insight into the course of Machupo virus infection in cynomolgus macaques and supports the usefulness of cynomolgus macaques as a viable model of human Machupo virus infection.

Giant thoracic schwannoma in a rhesus macaque (Macaca mulatta)

A 15-y-old male rhesus macaque with a 3-d history of labored breathing, was culled from a nonhuman primate research colony after thoracic radiographs and exploratory surgery revealed a 10-cm, well-circumscribed space-occupying mass in the posterior thoracic cavity. The multilobulated cystic and necrotic neoplasm was composed of interlacing streams and fascicles of neoplastic spindle cells arranged in Antoni A, and less commonly, Antoni B patterns. Verocay bodies were present also. The neoplasm was encapsulated mostly, and histomorphologic features were benign. Immunohistochemistry indicated that neoplastic cells were positive for vimentin, S100, glial fibrillary acidic protein, and nerve growth factor receptor. Reticulin histochemical staining and immunohistochemical stains for collagen IV and laminin showed a prominent basal lamina surrounding the neoplastic cells. The histologic features and results of the immunohistochemical stains confirmed peripheral nerve origin and were consistent with schwannoma. To our knowledge, this is the first case of thoracic schwannoma in a rhesus macaque and the second reported case of schwannoma in a nonhuman primate.

Assessment of two 'low-tech' genetic health care procedures performed by prenatal care providers in Washington state: implications for future policy development activities

Equity in health care demands that patients be treated fairly, impartially and with justice. Health care professionals and others have long been aware of the concept of equity, and the many inequities that exist in our health care system. As part of our analysis of postpartum data collected between 1993 and 1996 by the Washington Pregnancy Risk Assessment Monitoring System (PRAMS) from self-administered patient surveys, we explored equity as it pertains to two 'low-tech' prenatal genetic health care procedures: (1) whether or not prenatal care providers asked their patients about a family history of birth defects/genetic disorders, and (2) whether or not prenatal care providers talked to their patients about prenatal testing for birth defects/genetic disorders. Overall, about 80% of pregnant women reported that they had been asked about their family history of birth defects/genetic disorders, and about 85% said that their prenatal care provider(s) had talked to them about prenatal testing. Maternal characteristics associated with a lower likelihood of receiving these two low-tech genetic health care procedures appeared to be young maternal age, and low education and income levels, regardless of where women with these attributes received their prenatal care (e.g. community, migrant, health department or military health care clinics, private physicians, or health maintenance organizations).

Low-titre auto-antibodies predict autoimmune disease during interferon-alpha treatment of chronic hepatitis C

BACKGROUND

In this study, we determined whether low-titre auto-antibodies are a risk factor for the development of autoimmune disease during interferon-alpha (IFNalpha) therapy for chronic hepatitis C (CHC) infection.

METHODS

Eighty-three patients with circulating hepatitis C virus RNA and chronic viral hepatitis on liver biopsy, who had not received IFNalpha, were assessed for serum auto-antibodies (anti-nuclear antibodies (ANA), anti-smooth muscle antibodies, thyroid microsomal antibodies, thyroglobulin antibodies) and thyroid function tests.

RESULTS

Thirty-five patients had one or more pre-existing auto-antibody. The majority were low titre ANA. Seven of the 35 patients had clinical autoimmune disease or immune-mediated disorders, predominantly thyroid disease. Twenty patients with low titre auto-antibodies received treatment with IFNalpha and of these 20 patients, six patients developed adverse effects with a possible auto-immune basis. In comparison, only five of the 48 patients without auto-antibodies had immune-mediated disorders and no patient developed autoimmune complications during therapy with IFNalpha.

CONCLUSIONS

These results suggest that the presence of low-titre auto-antibodies may be a risk factor for the development of autoimmune dysfunction during IFNalpha therapy for chronic hepatitis C. Patients with no detectable auto-antibodies have a low risk for developing autoimmune complications during treatment with IFNalpha.

Viral etiology and epidemiology of acute respiratory infections in children in Nairobi, Kenya

Acute respiratory infection (ARI) is the most common cause of illness and death in young children worldwide. Because of inadequate laboratory facilities and financial resources the etiological agents responsible for most cases in developing countries remain unknown, thus obviating appropriate management. Therefore, an ARI program was commenced at the Kenyatta National Hospital, Nairobi, Kenya in 1981 with the objectives of establishing the microbial causes, clinical presentations, and diagnoses of ARI in children under 5 years of age and of developing simple, rapid, and inexpensive diagnostic techniques. Viruses were demonstrated in 54% of the 822 children studied, but over half of the viruses identified were types not commonly associated elsewhere with the causation of severe ARI. Respiratory syncytial, parainfluenza, and adenoviruses occurred in the same age groups and during similar weather conditions as elsewhere. Measles virus occurred most frequently in those 7 to 9 months old. Herpes simplex, rhino-, and enteroviruses play causative roles in some cases of severe ARI in Kenyan children. A combination of immunofluorescent and cell culture techniques were shown to be essential for the detection of viruses.

Investigation of the effectiveness of measles vaccination in children in Kenya

Laboratory studies were performed on 128 children clinically diagnosed as measles when seen at the Infectious Diseases Hospital, Kenyatta National Hospital (IDH), Nairobi (86 cases) and the Rural Health Training Centre, Maragua, Central Province (42 cases) between 9 July and 31 August 1984. A concurrent measles infection was confirmed in 95% of the children seen at IDH and in 85% of those seen at Maragua, with similar proportions of confirmations in children who had, and who had not, received measles vaccine. No differences in the number of sero-conversions nor in the absolute levels of acute or convalescent HI antibody titres could be detected between vaccinated and unvaccinated children. Analysis of the cases seen at Maragua indicates that about two thirds of the children who had received vaccine were protected. A pilot study of vaccinating children at 8 months and again at 12-13 months is suggested in an attempt to eradicate measles.

Detection of rotavirus by a latex agglutination test, Rotalex: comparison with electron microscopy, immunofluorescence, polyacrylamide gel electrophoresis, and enzyme linked immunosorbent assay

A commercially available latex agglutination test, Rotalex (Orion Diagnostics, Finland), for detecting rotaviruses was evaluated in comparison with four other tests (electron microscopy, immunofluorescence, polyacrylamide gel electrophoresis, and enzyme linked immunosorbent assay) routinely used in our laboratories. Although Rotalex was the least complex method, it showed lack of specificity and sensitivity when carried out according to the manufacturer's instructions. Four basic modifications of Rotalex are described. These include the use of Hank's balanced salt solution, increasing the incubation time to 20 min, reading the agglutination result by an experienced observer, and the use of 50 mm square glass plates. The modified procedure gave results which were comparable with those obtained by electron microscopy, immunofluorescence, polyacrylamide gel electrophoresis, and enzyme linked immunosorbent assay. The latter techniques, when used to detect rotavirus, all gave similar results.

The association of extrahepatic bile duct atresia and neonatal Epstein-Barr virus infection

An infant with uncorrectable extrahepatic bile duct atresia was found to have evidence of Epstein-Barr virus infection during the neonatal period. It is probable that the infection was acquired in utero. In view of the association of hepatitis with the Epstein-Barr virus in later life, it is possible that this infection was responsible for the development of bile duct obstruction.

Application of immunofluorescence to a study of measles

A new and rapid method for the laboratory diagnosis of measles, using the fluorescent antibody technique applied to nasopharyngeal secretions is described. The reliability of the method was best shown by correlation with clinical diagnosis, which gave an overall agreement of 95% in 53 cases of typical clinical measles and 72 control children. Correlation with results of tissue culture and serology was also good, though these methods are in practice too infrequently successful to be used as the main standards of reliability. The antiserum used for immunoflorescence showed no cross-reactivity with other viruses. Viruses could be identified by the fluorescent antibody technique from 4 days before to 10 days after the onset of the rash in a high proportion of cases. The wider applications of this method include rapid diagnosis of measles before the rash has appeared; in cases where clinical diagnosis is in doubt, especially in dark-skinned children, or when the illness has been modified by previous vaccination; prevention of cross-infection by early detection of measles; and investigation of the immune response and its relationship to nutritional status.

The relationship between measles virus infection and subacute sclerosing panencephalitis (SSPE)

On theoretical grounds we propose that the essential step in the development of subacute sclerosing panencephalitis (SSPE) after measles virus infection involves a reverse transcriptase-mediated change to a DNA form, probably brought about by co-infection with a leukovirus at a critical point in time. We further suggest that this new DNA then replicates either as the core of a new slow virus or as a membrane-attached viroid exhibiting a form of non-structural integration with host cell DNA resembling that found with the herpes viruses.