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Influenza A viruses (IAV) cause mammalian infections following several transmission routes. Considering the anatomic proximity and connection between the nasopharynx and periocular tissues, there is a need to understand the dynamics of virus spread between these sites following both respiratory and nonrespiratory viral transmission. We examined virus distribution and associated inflammation within nasal and periocular tissues during the acute phase of H1N1 IAV infection in ferrets following intranasal or ocular inoculation. Ocular and intranasal inoculations with IAV caused comparable viral antigen distribution and inflammation in the nasal passages, though infection kinetics and magnitude differed by inoculation route. Ocular inoculation was associated with inflammation in the conjunctiva and lacrimal glands. Although intranasal inoculation was also associated with periocular inflammation, the onset was delayed relative to ocular inoculation. This work underscores the importance of investigating extrapulmonary tissues following mammalian infection with respiratory pathogens, even after intranasal inoculation.

SARS-CoV-2 infection has been described in a wide range of species, including domestic animals such as dogs and cats. Illness in dogs is usually self-limiting, and further diagnostics may not be pursued if clinical signs resolve or they respond to empirical treatment. As new variants emerge, the clinical presentation and role in transmission may vary in animals. This report highlights different clinical presentations and immunological responses in two SARS-CoV-2 Delta-variant-positive dogs with similar exposure to the same fully vaccinated human with a SARS-CoV-2 infection and emphasizes the need for active surveillance and additional One Health research on SARS-CoV-2 variant infections in companion animals and other species.

Background No rabies post-exposure prophylaxis (PEP) failure has been documented in humans in the United States using modern cell-culture vaccines. In January 2021, an 84-year-old male died from rabies six months after being bitten by a rabid bat despite receiving timely rabies post-exposure prophylaxis (PEP). We investigated the cause of breakthrough infection. Methods We reviewed medical records, laboratory results, and autopsy findings, and performed whole genome sequencing (WGS) to compare patient and bat virus sequences. Storage, administration, and integrity of PEP biologics administered to the patient were assessed; samples from leftover rabies immunoglobulin were evaluated for potency. We conducted risk assessments for persons potentially exposed to the bat and for close contacts of the patient. Results Rabies virus antibodies present in serum and cerebrospinal fluid were non-neutralizing. Antemortem blood testing revealed the patient had unrecognized monoclonal gammopathy of unknown significance. Autopsy findings showed rabies meningoencephalitis and metastatic prostatic adenocarcinoma. Rabies virus sequences from the patient and the offending bat were identical by WGS. No deviations were identified in potency, quality control, administration, or storage of administered PEP. Of 332 persons assessed for potential rabies exposure to the case patient, three (0.9%) warranted PEP. Conclusion This is the first reported failure of rabies PEP in the Western Hemisphere using a cell culture vaccine. Host-mediated primary vaccine failure attributed to previously unrecognized impaired immunity is the most likely explanation for this breakthrough infection. Clinicians should consider measuring rabies neutralizing antibody titers after completion of PEP if there is any suspicion for immunocompromise.

Background Minimally invasive tissue sampling (MITS), an alternative to complete diagnostic autopsy, is a pathology-based postmortem examination that has been validated in low- and middle-income countries (LMICs) and can provide accurate cause of death information when used with other data. The MITS Surveillance Alliance was established in 2017 with the goal to expand MITS globally by increasing training capacity, accessibility, and availability in LMICs. Between January 2019 and May 2020, the MITS Surveillance Alliance convened a multidisciplinary team of technical advisors to attain this goal. Methods This article describes the process used to develop criteria and identify an optimal location for a MITS training hub, establish a cadre of LMIC-based trainers, refine standardized MITS sample collection protocols, develop a training program, and release a telepathology platform for quality assessment of MITS histological samples. Results Results include the creation of a training hub and curriculum, with a total of 9 pathologists and technicians trained as part of the training of the trainers. Those trainers trained 15 participants from seven MITS projects representing 6 LMICs trained in MITS sample collection. The 15 participants have gone on to train more than 50 project-level staff in MITS sample collection. Conclusions Lessons learned include an appreciation for using an iterative process for establishing standardized procedures, creating opportunities for all stakeholders to deliver critical feedback, and highlighting the importance of complementing in-person trainings with ongoing technical assistance.

Background Minimally invasive tissue sampling (MITS) is an alternative to complete autopsy for determining causes of death. Multiplex molecular testing performed on MITS specimens poses challenges of interpretation, due to high sensitivity and indiscriminate detection of pathogenic, commensal, or contaminating microorganisms. Methods MITS was performed on 20 deceased children with respiratory illness, at 10 timepoints up to 88 hours postmortem. Samples were evaluated by multiplex molecular testing on fresh tissues by TaqMan® Array Card (TAC) and by histopathology, special stains, immunohistochemistry (IHC), and molecular testing (PCR) on formalin-fixed, paraffin-embedded (FFPE) tissues. Results were correlated to determine overall pathologic and etiologic diagnoses and to guide interpretation of TAC results. Results MITS specimens collected up to 3 days postmortem were adequate for histopathologic evaluation and testing. Seven different etiologic agents were detected by TAC in 10 cases. Three cases had etiologic agents detected by FFPE or other methods and not TAC; 2 were agents not present on TAC, and 2 were streptococci that may have been species other than those present on TAC. Result agreement was 43% for TAC and IHC or PCR, and 69% for IHC and PCR. Extraneous TAC results were common, especially when aspiration was present. Conclusions TAC can be performed on MITS up to 3 days after death with refrigeration and provides a sensitive method for detection of pathogens but requires careful interpretation in the context of clinicoepidemiologic and histopathologic findings. Interpretation of all diagnostic tests in aggregate to establish overall case diagnoses maximizes the utility of TAC in MITS.

OBJECTIVE To establish a pathoepidemiological model to evaluate the role of SARS-CoV-2 infection in the first 10 companion animals that died while infected with SARS-CoV-2 in the US. ANIMALS 10 cats and dogs that tested positive for SARS-CoV-2 and died or were euthanized in the US between March 2020 and January 2021. PROCEDURES A standardized algorithm was developed to direct case investigations, determine the necessity of certain diagnostic procedures, and evaluate the role, if any, that SARS-CoV-2 infection played in the animals’ course of disease and death. Using clinical and diagnostic information collected by state animal health officials, state public health veterinarians, and other state and local partners, this algorithm was applied to each animal case. RESULTS SARS-CoV-2 was an incidental finding in 8 animals, was suspected to have contributed to the severity of clinical signs leading to euthanasia in 1 dog, and was the primary reason for death for 1 cat. CONCLUSIONS AND CLINICAL RELEVANCE This report provides the global community with a standardized process for directing case investigations, determining the necessity of certain diagnostic procedures, and determining the clinical significance of SARS-CoV-2 infections in animals with fatal outcomes and provides evidence that SARS-CoV-2 can, in rare circumstances, cause or contribute to death in pets.

Development of lethal models of Ebola virus disease has been achieved by the serial passage of virus isolates from human cases in mice and guinea pigs. Use of mice infected with non-adapted virus has been limited due to the absence of overt clinical disease. In recent years, newly recognized sequelae identified in human cases has highlighted the importance of continued investigations of non-lethal infection both in humans and animal models. Here, we revisit the use of rodent-adapted and non-adapted Ebola virus (EBOV) variants in mice to investigate infection tolerance and future utility of these models in pathogenesis and therapeutic intervention studies. We found that like non-adapted wild-type EBOV, guinea pig-adapted EBOV results in widespread tissue infection, variably associated with tissue pathology, and alterations in clinical and immunological analytes in the absence of overt disease. Notably, infection with either non-lethal variant does not greatly differ from lethal mouse-adapted EBOV until near the time end-point criteria are reached in these mice, supporting use of these models of virus tolerance for continued investigations of non-lethal infection and sequelae.

As of October 21, 2022, a total of 27,884 monkeypox cases (confirmed and probable) have been reported in the United States.

Human infection with Sosuga virus (SOSV), a recently discovered pathogenic paramyxovirus, has been reported in one individual to date. No animal models of disease are currently available for SOSV. Here, we describe initial characterization of experimental infection in Syrian hamsters, including kinetics of virus dissemination and replication, and the corresponding clinical parameters, immunological responses, and histopathology. We demonstrate susceptibility of hamsters to infection in the absence of clinical signs or significant histopathologic findings in tissues.

As of October 11, 2022, a total of 26,577 monkeypox cases had been reported in the United States.* Although most cases of monkeypox are self-limited, lesions that involve anatomically vulnerable sites can cause complications. Ocular monkeypox can occur when Monkeypox virus (MPXV) is introduced into the eye (e.g., from autoinoculation), potentially causing conjunctivitis, blepharitis, keratitis, and loss of vision (1). This report describes five patients who acquired ocular monkeypox during July-September 2022. All patients received treatment with tecovirimat (Tpoxx)

Leptospirosis is a zoonotic neglected disease of worldwide public health concern. Leptospira species can infect a wide range of wild and domestic mammals and lead to a spectrum of disease, including severe and fatal forms. Herein, we report for the first time a fatal Leptospira interrogans infection in a free-ranging nonhuman primate (NHP), a black-tufted marmoset. Icterus, pulmonary haemorrhage, interstitial nephritis, and hepatocellular dissociation were the main findings raising the suspicion of leptospirosis. Diagnostic confirmation was based on specific immunohistochemical and PCR assays for Leptospira species. Immunolocalization of leptospiral antigens and identification of pathogenic species (L. interrogans species) were important for better understanding the pathogenesis of the disease. One Health-related implications of free-ranging NHPs in anthropized areas and transmission dynamics of human and animal leptospirosis are discussed.

Canine leproid granuloma (CLG) is a chronic form of dermatitis that has been associated with nontuberculous mycobacterial infections in Africa, Oceania, the Americas, and Europe. We report here a case of CLG associated with a member of the Mycobacterium tuberculosis complex (MTBC), which could be of public health concern. An 8-y-old pet dog developed 0.5–1-cm diameter, raised, firm, nonpruritic, alopecic, painless skin nodules on the external aspects of both pinnae. Histologic examination revealed severe pyogranulomatous dermatitis with intracellular Ziehl-Neelsen–positive bacilli that were immunoreactive by immunohistochemistry using a polyclonal primary antibody that recognizes tuberculous and nontuberculous Mycobacterium species. DNA extracted from formalin-fixed, paraffin-embedded skin sections was tested by a Mycobacterium genus–specific nested PCR assay targeting the 16S rRNA gene. BLAST sequence analysis of 214-bp and 178-bp amplicons showed 99.5% identity with members of the MTBC; however, the agent could not be identified at the species level. Although CLG has been associated traditionally with nontuberculous mycobacterial infections, the role of Mycobacterium spp. within the MTBC as a cause of this condition, and the role of dogs with CLG as possible sources of MTBC to other animals and humans, should not be disregarded given its zoonotic potential.

A 56-year-old man receiving rituximab who had months of neurologic symptoms was found to have Jamestown Canyon virus in cerebrospinal fluid by clinical metagenomic sequencing. The patient died, and postmortem examination revealed extensive neuropathologic abnormalities. Deep sequencing enabled detailed characterization of viral genomes from the cerebrospinal fluid, cerebellum, and cerebral cortex.

Toxoplasmosis is an important zoonotic disease that affects a wide range of warm-blooded host species. Neotropical primates (New World Primates; NWP) are highly susceptible, developing a lethal acute systemic disease. Toxoplasmosis in free-ranging NWP is poorly described, with only a few studies based on serosurveys. Herein we performed a retrospective study focusing on the epidemiology and pathology of toxoplasmosis among 1,001 free-ranging marmoset (Callithrix spp.) deaths from the Brazilian Atlantic Forest. This study included marmosets necropsied at the Instituto Municipal de Medicina Veterinária Jorge Vaitsman (IJV) from January 2017 to July 2019, which were found dead from all regions in the State of Rio de Janeiro. Histopathology, immunohistochemistry, and transmission electron microscopy were performed to better characterize toxoplasmosis in this free-ranging population. All samples were also tested for Yellow Fever Virus (YFV) RT-qPCR by the official diagnostic service. A total of 1,001 free-ranging marmosets were included in this study, with 16 (1.6%) cases of lethal Toxoplasma gondii infections identified both as individual cases and in outbreaks. Presence of infection was not associated with sex, age, geographical distribution, or year of death, and no co-infection with YFV was observed. The main pathological feature in these cases was random necrotizing hepatitis with detection of intralesional T. gondii zoites in all infected cases. Interstitial pneumonia rich in alveolar foamy macrophages and fibrin deposition, necrotizing myocarditis and necrotizing splenitis were also pathological features in affected marmosets. Therefore, toxoplasmosis was considered the cause of death in 1.6% of free-ranging marmosets in this retrospective series, including some cases associated with outbreaks. Necrotizing random hepatitis was a consistent pathological finding in affected cases and sampling of liver should be ensured from Callitrichid post mortem cases.

On April 20, 2018, the Kween District Health Office in Kween District, Uganda reported 7 suspected cases of human anthrax. A team from the Uganda Ministry of Health and partners investigated and identified 49 cases, 3 confirmed and 46 suspected; no deaths were reported. Multiple exposures from handling the carcass of a cow that had died suddenly were significantly associated with cutaneous anthrax, whereas eating meat from that cow was associated with gastrointestinal anthrax. Eating undercooked meat was significantly associated with gastrointestinal anthrax, but boiling the meat for >60 minutes was protective. We recommended providing postexposure antimicrobial prophylaxis for all exposed persons, vaccinating healthy livestock in the area, educating farmers to safely dispose of animal carcasses, and avoiding handling or eating meat from livestock that died of unknown causes.

Summary Background Since August, 2019, US public health officials have been investigating a national outbreak of e-cigarette, or vaping, product use-associated lung injury (EVALI). A spectrum of histological patterns consistent with acute to subacute lung injury has been seen in biopsies; however, autopsy findings have not been systematically characterised. We describe the pathological findings in autopsy and biopsy tissues submitted to the US Centers for Disease Control and Prevention (CDC) for the evaluation of suspected EVALI. Methods Between Aug 1, 2019, and Nov 30, 2019, we examined lung biopsy (n=10 individuals) and autopsy (n=13 individuals) tissue samples received by the CDC, submitted by 16 US states, from individuals with: a history of e-cigarette, or vaping, product use; respiratory, gastrointestinal, or constitutional symptoms; and either pulmonary infiltrates or opacities on chest imaging, or sudden death from an undetermined cause. We also reviewed medical records, evaluated histopathology, and performed infectious disease testing when indicated by histopathology and clinical history. Findings 21 cases met surveillance case definitions for EVALI, with a further two cases of clinically suspected EVALI evaluated. All ten lung biopsies showed histological evidence of acute to subacute lung injury, including diffuse alveolar damage or organising pneumonia. These patterns were also seen in nine of 13 (69%) autopsy cases, most frequently diffuse alveolar damage (eight autopsies), but also acute and organising fibrinous pneumonia (one autopsy). Additional pulmonary pathology not necessarily consistent with EVALI was seen in the remaining autopsies, including bronchopneumonia, bronchoaspiration, and chronic interstitial lung disease. Three of the five autopsy cases with no evidence of, or a plausible alternative cause for acute lung injury, had been classified as confirmed or probable EVALI according to surveillance case definitions. Interpretation Acute to subacute lung injury patterns were seen in all ten biopsies and most autopsy lung tissues from individuals with suspected EVALI. Acute to subacute lung injury can have numerous causes; however, if it is identified in an individual with a history of e-cigarette, or vaping, product use, and no alternative cause is apparent, a diagnosis of EVALI should be strongly considered. A review of autopsy tissue pathology in suspected EVALI deaths can also identify alternative diagnoses, which can enhance the specificity of public health surveillance efforts. Funding US Centers for Disease Control and Prevention.

An ongoing pandemic of coronavirus disease (COVID-19) is caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Characterization of the histopathology and cellular localization of SARS-CoV-2 in the tissues of patients with fatal COVID-19 is critical to further understand its pathogenesis and transmission and for public health prevention measures. We report clinicopathologic, immunohistochemical, and electron microscopic findings in tissues from 8 fatal laboratory-confirmed cases of SARS-CoV-2 infection in the United States. All cases except 1 were in residents of long-term care facilities. In these patients, SARS-CoV-2 infected epithelium of the upper and lower airways with diffuse alveolar damage as the predominant pulmonary pathology. SARS-CoV-2 was detectable by immunohistochemistry and electron microscopy in conducting airways, pneumocytes, alveolar macrophages, and a hilar lymph node but was not identified in other extrapulmonary tissues. Respiratory viral co-infections were identified in 3 cases; 3 cases had evidence of bacterial co-infection.

- Label: BACKGROUND NlmCategory: BACKGROUND content: "Sub-Saharan Africa and south Asia contributed 81% of 5\xC2\xB79 million under-5 deaths and 77% of 2\xC2\xB76 million stillbirths worldwide in 2015. Vital registration and verbal autopsy data are mainstays for the estimation of leading causes of death, but both are non-specific and focus on a single underlying cause. We aimed to provide granular data on the contributory causes of death in stillborn fetuses and in deceased neonates and children younger than 5 years, to inform child mortality prevention efforts." - Label: METHODS NlmCategory: METHODS content: "The Child Health and Mortality Prevention Surveillance (CHAMPS) Network was established at sites in seven countries (Baliakandi, Bangladesh; Harar and Kersa, Ethiopia; Siaya and Kisumu, Kenya; Bamako, Mali; Manhi\xC3\xA7a, Mozambique; Bombali, Sierra Leone; and Soweto, South Africa) to collect standardised, population-based, longitudinal data on under-5 mortality and stillbirths in sub-Saharan Africa and south Asia, to improve the accuracy of determining causes of death. Here, we analysed data obtained in the first 2 years after the implementation of CHAMPS at the first five operational sites, during which surveillance and post-mortem diagnostics, including minimally invasive tissue sampling (MITS), were used. Data were abstracted from all available clinical records of deceased children, and relevant maternal health records were also extracted for stillbirths and neonatal deaths, to incorporate reported pregnancy or delivery complications. Expert panels followed standardised procedures to characterise causal chains leading to death, including underlying, intermediate (comorbid or antecedent causes), and immediate causes of death for stillbirths, neonatal deaths, and child (age 1-59 months) deaths." - Label: FINDINGS NlmCategory: RESULTS content: Between Dec 10, 2016, and Dec 31, 2018, MITS procedures were implemented at five sites in Mozambique, South Africa, Kenya, Mali, and Bangladesh. We screened 2385 death notifications for inclusion eligibility, following which 1295 families were approached for consent; consent was provided for MITS by 963 (74%) of 1295 eligible cases approached. At least one cause of death was identified in 912 (98%) of 933 cases (180 stillbirths, 449 neonatal deaths, and 304 child deaths); two or more conditions were identified in the causal chain for 585 (63%) of 933 cases. The most common underlying causes of stillbirth were perinatal asphyxia or hypoxia (130 [72%] of 180 stillbirths) and congenital infection or sepsis (27 [15%]). The most common underlying causes of neonatal death were preterm birth complications (187 [42%] of 449 neonatal deaths), perinatal asphyxia or hypoxia (98 [22%]), and neonatal sepsis (50 [11%]). The most common underlying causes of child deaths were congenital birth defects (39 [13%] of 304 deaths), lower respiratory infection (37 [12%]), and HIV (35 [12%]). In 503 (54%) of 933 cases, at least one contributory pathogen was identified. Cytomegalovirus, Escherichia coli, group B Streptococcus, and other infections contributed to 30 (17%) of 180 stillbirths. Among neonatal deaths with underlying prematurity, 60% were precipitated by other infectious causes. Of the 275 child deaths with infectious causes, the most common contributory pathogens were Klebsiella pneumoniae (86 [31%]), Streptococcus pneumoniae (54 [20%]), HIV (40 [15%]), and cytomegalovirus (34 [12%]), and multiple infections were common. Lower respiratory tract infection contributed to 174 (57%) of 304 child deaths. - Label: INTERPRETATION NlmCategory: CONCLUSIONS content: Cause of death determination using MITS enabled detailed characterisation of contributing conditions. Global estimates of child mortality aetiologies, which are currently based on a single syndromic cause for each death, will be strengthened by findings from CHAMPS. This approach adds specificity and provides a more complete overview of the chain of events leading to death, highlighting multiple potential interventions to prevent under-5 mortality and stillbirths. - Label: FUNDING NlmCategory: BACKGROUND content: Bill & Melinda Gates Foundation.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes respiratory disease in mink similar to human COVID-19. We characterized the pathological findings in 72 mink from US farms with SARS-CoV-2 outbreaks, localized SARS-CoV-2 and its host cellular receptor angiotensin-converting enzyme 2 (ACE2) in mink respiratory tissues, and evaluated the utility of various test methods and specimens for SARS-CoV-2 detection in necropsy tissues. Of SARS-CoV-2-positive animals found dead, 74% had bronchiolitis and diffuse alveolar damage (DAD). Of euthanized SARS-CoV-2-positive animals, 72% had only mild interstitial pneumonia or minimal nonspecific lung changes (congestion, edema, macrophages); similar findings were seen in SARS-CoV-2-negative animals. Suppurative rhinitis, lymphocytic perivascular inflammation in the lungs, and lymphocytic infiltrates in other tissues were common in both SARS-CoV-2-positive and SARS-CoV-2-negative animals. In formalin-fixed paraffin-embedded (FFPE) upper respiratory tract (URT) specimens, conventional reverse transcription-polymerase chain reaction (cRT-PCR) was more sensitive than in situ hybridization (ISH) or immunohistochemistry (IHC) for detection of SARS-CoV-2. FFPE lung specimens yielded less detection of virus than FFPE URT specimens by all test methods. By IHC and ISH, virus localized extensively to epithelial cells in the nasal turbinates, and prominently within intact epithelium; olfactory mucosa was mostly spared. The SARS-CoV-2 receptor ACE2 was extensively detected by IHC within turbinate epithelium, with decreased detection in lower respiratory tract epithelium and alveolar macrophages. This study expands on the knowledge of the pathology and pathogenesis of natural SARS-CoV-2 infection in mink and supports their further investigation as a potential animal model of SARS-CoV-2 infection in humans.

Background We used postmortem minimally invasive tissue sampling (MITS) to assess the effect of time since death on molecular detection of pathogens among respiratory illness–associated deaths. Methods Samples were collected from 20 deceased children (aged 1–59 months) hospitalized with respiratory illness from May 2018 through February 2019. Serial lung and/or liver and blood samples were collected using MITS starting soon after death and every 6 hours thereafter for up to 72 hours. Bodies were stored in the mortuary refrigerator for the duration of the study. All specimens were analyzed using customized multipathogen TaqMan® array cards (TACs). Results We identified a median of 3 pathogens in each child’s lung tissue (range, 1–8; n = 20), 3 pathogens in each child’s liver tissue (range, 1–4; n = 5), and 2 pathogens in each child’s blood specimen (range, 0–4; n = 5). Pathogens were not consistently detected across all collection time points; there was no association between postmortem interval and the number of pathogens detected (P = .43) and no change in TAC cycle threshold value over time for pathogens detected in lung tissue. Human ribonucleoprotein values indicated that specimens collected were suitable for testing throughout the study period. Conclusions Results suggest that lung, liver, and blood specimens can be collected using MITS procedures up to 4 days after death in adequately preserved bodies. However, inconsistent pathogen detection in samples needs careful consideration before drawing definitive conclusions on the etiologic causes of death.

A 70-day-old Boxer dog from a household in Montevideo, Uruguay, died after presenting neurologic, respiratory, and gastrointestinal signs for 6 days. Autopsy findings included lymphadenomegaly, ascites and hepatomegaly. Histopathology revealed severe widespread lymphohistiocytic and plasmacytic myocarditis with cardiomyocyte necrosis, mineralization and numerous intrasarcoplasmic protozoa immunoreactive with anti-Toxoplasma gondii antisera on immunohistochemistry. The protozoa were ultrastructurally confirmed as T. gondii by transmission electron microscopy. Other lesions included diffuse centrilobular hepatocellular necrosis, multifocal lymphohistiocytic portal hepatitis and interstitial nephritis. Other causes of myocarditis, including Neospora caninum, Trypanosoma cruzi, Sarcocystis neurona, canine distemper virus, and canine parvovirus were ruled out by immunohistochemistry. Toxoplasma gondii infections in dogs are usually subclinical; however, clinical disease with fatal outcome can occur. To our knowledge, this is the first report of fatal toxoplasmosis in a dog in Uruguay. This case raises awareness for dogs as sentinels and possible sources of human toxoplasmosis in urban settings in Uruguay.

Smallpox, caused by the solely human pathogen Variola virus (VARV), was declared eradicated in 1980. While known VARV stocks are secure, smallpox remains a bioterrorist threat agent. Recent U.S. Food and Drug Administration approval of the first smallpox anti-viral (tecovirimat) therapeutic was a successful step forward in smallpox preparedness; however, orthopoxviruses can become resistant to treatment, suggesting a multi-therapeutic approach is necessary. Animal models are required for testing medical countermeasures (MCMs) and ideally MCMs are tested directly against the pathogen of interest. Since VARV only infects humans, a representative animal model for testing therapeutics directly against VARV remains a challenge. Here we show that three different humanized mice strains are highly susceptible to VARV infection, establishing the first small animal model using VARV. In comparison, the non-humanized, immunosuppressed background mouse was not susceptible to systemic VARV infection. Following an intranasal VARV challenge that mimics the natural route for human smallpox transmission, the virus spread systemically within the humanized mouse before mortality (~ 13 days post infection), similar to the time from exposure to symptom onset for ordinary human smallpox. Our identification of a permissive/representative VARV animal model can facilitate testing of MCMs in a manner consistent with their intended use., Author summary Preparedness activities against highly transmissible respiratory viruses with high mortality have been highlighted during the ongoing COVID-19 pandemic. Smallpox, caused by Variola virus (VARV) infection, is highly transmissible and estimated to have killed 300 million people in the 20th century alone with ~30% mortality. Through an intensive vaccination campaign smallpox was declared eradicated in 1980 and routine smallpox vaccination of individuals ceased. Today’s population has little/no immunity against VARV; if smallpox were to re-emerge the worldwide results would be devastating. Development of antiviral strategies is critical for outbreak response efforts and in order to truly gauge the potential effectiveness of a medical countermeasure (MCM), it must be tested directly against the pathogen. VARV is solely a human pathogen and infections of surrogate animal models have been largely unsuccessful. Here we use the humanized mouse to establish the first small animal model using VARV. We found that the virus spread systemically within humanized mice before mortality (~ 13 days post infection), similar to the time from exposure to symptom onset for ordinary human smallpox. These findings improve upon current MCM efficacy testing methods by providing a means to conduct in vivo evaluations of smallpox MCMs directly against VARV.

Leptospirosis is a zoonotic neglected disease of worldwide public health concern. Leptospira species can infect a wide range of wild and domestic mammals and can lead to a spectrum of disease, including severe and fatal forms. Herein, we report for the first time a fatal Leptospira interrogans infection in a free-ranging nonhuman primate (NHP), a black-tufted marmoset. Icterus, pulmonary hemorrhage, interstitial nephritis and hepatocellular dissociation were the main findings raising the suspicion of leptospirosis. Diagnostic confirmation was based on specific immunohistochemical and PCR assays for Leptospira species. Immunolocalization of leptospiral antigens and identification of pathogenic species ( L. interrogans species) were important for better understanding the pathogenesis of disease. One Health related implications of free-ranging NHPs in anthropized areas and transmission dynamics of human and animal leptospirosis are discussed.

Abrin is a toxin of public health concern due to its lethality, lack of antidote, and potential for use as a bioterrorism agent. Possible routes of exposure include ingestion, inhalation, and injection. Onset of symptoms is often delayed, even in severe cases. In fatal cases, death occurs from multi-organ failure. We describe the clinical course, laboratory, and pathologic findings in a case of fatal human poisoning associated with abrin injection. The Abrus precatorius seeds in this case were obtained via the internet. The Centers for Disease Control and Prevention's Laboratory Response Network detected abrine in the urine confirming abrin exposure in this fatal poisoning.

Background Postmortem minimally invasive tissue sampling (MITS) is a potential alternative to the gold standard complete diagnostic autopsy for identifying specific causes of childhood deaths. We investigated the utility of MITS, interpreted with available clinical data, for attributing underlying and immediate causes of neonatal deaths. Methods This prospective, observational pilot study enrolled neonatal deaths at Chris Hani Baragwanath Academic Hospital in Soweto, South Africa. The MITS included needle core-biopsy sampling for histopathology of brain, lung, and liver tissue. Microbiological culture and/or molecular tests were performed on lung, liver, blood, cerebrospinal fluid, and stool samples. The “underlying” and “immediate” causes of death (CoD) were determined for each case by an international panel of 12–15 medical specialists. Results We enrolled 153 neonatal deaths, 106 aged 3–28 days. Leading underlying CoD included “complications of prematurity” (52.9%), “complications of intrapartum events” (15.0%), “congenital malformations” (13.1%), and “infection related” (9.8%). Overall, infections were the immediate or underlying CoD in 57.5% (n = 88) of all neonatal deaths, including the immediate CoD in 70.4% (58/81) of neonates with “complications of prematurity” as the underlying cause. Overall, 74.4% of 90 infection-related deaths were hospital acquired, mainly due to multidrug-resistant Acinetobacter baumannii (52.2%), Klebsiella pneumoniae (22.4%), and Staphylococcus aureus (20.9%). Streptococcus agalactiae was the most common pathogen (5/15 [33.3%]) among deaths with “infections” as the underlying cause. Conclusions MITS has potential to address the knowledge gap on specific causes of neonatal mortality. In our setting, this included the hitherto underrecognized dominant role of hospital-acquired multidrug-resistant bacterial infections as the leading immediate cause of neonatal deaths., Minimally invasive tissue sampling and clinical history were utilized to attribute cause of death in South African neonates. Leading underlying causes of death were prematurity, complications of intrapartum events, and congenital malformations. The leading immediate cause of death was infection.

Introduction: Acanthamoeba spp. is a ubiquitous free-living amoeba that causes human infections affecting predominantly the cornea and central nervous system. The diagnosis and treatment of Acantha...

Prior to the emergence of Asian genotype Zika virus (ZIKV) in the Western hemisphere, sexual transmission in humans was documented. Sexual transmission by African genotype ZIKVs has not been assessed in laboratory animal models, due to rapid and high mortality rates of immunodeficient mice following inoculation. To overcome these limitations, immunocompetent C57Bl/6 mice were used to longitudinally assess Asian and African genotype ZIKV sexual transmission potential. Furthermore, to determine if enhanced pathogenesis of African genotype ZIKVs is due to structural determinants, PRVABC59 prM/E was replaced with African MR766 prM/E (chimeric ZIKV). The African genotype and chimeric ZIKV elicited greater pathogenic effects in the male reproductive tract and generated higher viremias. Yet, the duration, magnitude and efficiency of seminal shedding of infectious virus and viral RNA were similar between chimeric-, African and Asian genotype ZIKV-inoculated mice. These data show that increased male reproductive tract pathology does not increase sexual transmission potential.

Lassa virus (LASV), a hemorrhagic fever virus endemic to West Africa, causes conjunctivitis in patients with acute disease. To examine ocular manifestations of LASV, we histologically examined eyes from infected guinea pigs. In fatal disease, LASV immunostaining was most prominent in the anterior uvea, especially in the filtration angle, ciliary body, and iris and in and around vessels in the bulbar conjunctiva and peripheral cornea, where it co-localized with an endothelial marker (platelet endothelial cell adhesion molecule). Antigen was primarily associated with infiltration of T-lymphocytes around vessels in the anterior uvea and with new vessel formation at the peripheral cornea. In animals that exhibited clinical signs but survived infection, eyes had little to no inflammation and no LASV immunostaining 6 weeks after infection. Overall, in this model, LASV antigen was restricted to the anterior uvea and was associated with mild chronic inflammation in animals with severe disease but was not detected in survivors.

Zika virus (ZIKV) infection can result in neurological disorders including Congenital Zika Syndrome in infants exposed to the virus in utero. Pregnant women can be infected by mosquito bite as well as by sexual transmission from infected men. Herein, the variants of ZIKV within the male reproductive tract and ejaculates were assessed in inoculated mice. We identified two non-synonymous variants at positions E-V330L and NS1-W98G. These variants were also present in the passage three PRVABC59 isolate and infectious clone relative to the patient serum PRVABC59 sequence. In subsequent studies, ZIKV E-330L was less pathogenic in mice than ZIKV E-330V as evident by increased average survival times. In Vero cells, ZIKV E-330L/NS1-98G outcompeted ZIKV E-330V/NS1-98W within 3 passages. These results suggest that the E-330L/NS1-98G variants are attenuating in mice and were enriched during cell culture passaging. Cell culture propagation of ZIKV could significantly affect animal model development and vaccine efficacy studies. NIH [AI067380] This work was supported in part by NIH grant AI067380 (G.D.E.). We thank DVBD staff members Jason Velez for cell culture support and Sean Masters for his excellent contributions to animal husbandry and animal care needs throughout this study. The findings and conclusions of this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention or the U.S. Agency for International Development.