The influence of gender and temephos exposure on community participation in dengue prevention: a compartmental mathematical model.

BACKGROUND: The use of temephos, the most common intervention for the chemical control of Aedes aegypti over the last half century, has disappointing results in control of the infection. The footprint of Aedes and the diseases it carries have spread relentlessly despite massive volumes of temephos. Recent advances in community participation show this might be more effective and sustainable for the control of the dengue vector. METHODS: Using data from the Camino Verde cluster randomized controlled trial, a compartmental mathematical model examines the dynamics of dengue infection with different levels of community participation, taking account of gender of respondent and exposure to temephos. RESULTS: Simulation of dengue endemicity showed community participation affected the basic reproductive number of infected people. The greatest short-term effect, in terms of people infected with the virus, was the combination of temephos intervention and community participation. There was no evidence of a protective effect of temephos 220 days after the onset of the spread of dengue. CONCLUSIONS: Male responses about community participation did not significantly affect modelled numbers of infected people and infectious mosquitoes. Our model suggests that, in the long term, community participation alone may have the best results. Adding temephos to community participation does not improve the effect of community participation alone.

Depression and associated factors in medical students in Acapulco during the COVID-19 pandemic: A cross-sectional study.

BACKGROUND: Depression is common in medical students and the Mexican state of Guerrero has the highest rates of depression in the country. Acapulco, the seat of the state medical school, is a tourist destination that experienced early high rates of COVID-19. The COVID-19 pandemic closed all schools in Mexico, obliging a shift from face-to-face to virtual education. In this new context, medical students faced challenges of online teaching including inadequate connectivity and access technologies. Prolonged isolation during the pandemic may have had additional mental health implications. AIM: Assess depression prevalence and its associated factors affecting medical students in Acapulco, Mexico during the COVID-19 pandemic. METHODS: A cross-sectional survey of students of the Faculty of Medicine of the Universidad Autónoma de Guerrero, in November 2020. After informed consent, students completed a self-administered questionnaire collating socio-demographic, academic and clinical variables, major life events and changes in mood. The Beck inventory provided an assessment of depression. Bivariate and multivariate analyses relied on the Mantel-Haenszel procedure to identify factors associated with depression. We estimated the odds ratio (OR) and 95% confidence intervals. RESULTS: 33.8% (435/1288) of student questionnaires showed evidence of depression in the two weeks prior to the study, with 39.9% (326/817) of young women affected. Factors associated with depression included female sex (OR 1.95; 95%CI 1.48-2.60), age 18-20 years (OR 1.36; 95%CI 1.05-1.77), perceived academic performance (OR 2.97; 95%CI 2.16-4.08), perceived economic hardship (OR 2.18; 95%CI 1.57-3.02), and a family history of depression (OR 1.85; 95%CI 10.35-2.54). Covid-19 specific factors included a life event during the pandemic (OR 1.99; 95%CI 1.54-2.59), connectivity problems during virtual classes and difficulties accessing teaching materials (OR 1.75; 95%CI 1.33-2.30). CONCLUSIONS: The high risk of depression in medical students during the COVID-19 pandemic was associated with perceived academic performance and technical barriers to distance learning, in addition to known individual and family factors. This evidence may be useful for the improvement of programs on prevention and control of depression in university students.

Occurrence of scorpion sting and associated factors in a highly marginalized municipality in Guerrero, Mexico: A cross-sectional study.

BACKGROUND: Scorpion sting is a neglected public health problem, despite a global estimate of 1.2 million scorpion stings and some 3,250 deaths annually. METHODS: This cross-sectional study estimates the occurrence of scorpion stings and identifies associated factors in seven communities in the highly marginalized municipality of Chilapa, in the Mexican state of Guerrero. After informed consent, 1,144 households provided information on 4,985 residents. The questionnaire collated sociodemographic data, characteristics of the dwelling, efforts to avoid scorpion stings, and individual information of scorpion stings suffered in the last year. Cluster-adjusted (acl), bivariate and multivariate analysis relied on the Mantel-Haenszel procedure. RESULTS: The overall period prevalence of scorpion stings in the year prior to the study was 4.4% (218/4985), 5.4% in men (126/2320), and 3.5% in women (92/2665), p<0.01. The majority occurred at home 68.3% (149/218), followed by agricultural fields 26.6% (58/218), street 2.8% (6/218), and work 2.3% (5/218). Factors associated with scorpion sting were carrying firewood (OR 2.1; CI95%acl 1.40-3.09), keeping free-range hens around of the home (OR 1.9; CI95%acl 1.19-2.85), residing in a rural area (OR 1.7; CI95%acl 1.04-2.78), being male (OR 1.6; CI95%acl 1.18-2.28), and helping with housework (OR 1.6; CI95%acl 1.04-2.40). CONCLUSION: This study confirms scorpion bites are a public health problem in these marginalized communities in Guerrero State, with risk factors related to living conditions and the work process at home and in the fields. Almost all risk factors identified could be reduced with low-cost interventions implemented by the communities themselves.

Pulmonary insults exacerbate susceptibility to oral Listeria monocytogenes infection through the production of IL-10 by NK cells.

Most individuals who consume foods contaminated with the bacterial pathogen Listeria monocytogenes (Lm) develop mild symptoms, while others are susceptible to life-threatening systemic infections (listeriosis). Although it is known that the risk of severe disease is increased in certain human populations, including the elderly, it remains unclear why others who consume contaminated food develop listeriosis. Here, we used a murine model to discover that pulmonary coinfections can impair the host's ability to adequately control and eradicate systemic Lm that cross from the intestines to the bloodstream. We found that the resistance of mice to oral Lm infection was dramatically reduced by coinfection with Streptococcus pneumoniae (Spn), a bacterium that colonizes the respiratory tract and can also cause severe infections in the elderly. Exposure to Spn or microbial products, including a recombinant Lm protein (L1S) and lipopolysaccharide (LPS), rendered otherwise resistant hosts susceptible to severe systemic Lm infection. In addition, we show that this increase in susceptibility was dependent on an increase in the production of interleukin-10 (IL-10) from Ncr1+ cells, including natural killer (NK) cells. Lastly, the ability of Ncr1+ cell derived IL-10 to increase disease susceptibility correlated with a dampening of both myeloid cell accumulation and myeloid cell phagocytic capacity in infected tissues. These data suggest that efforts to minimize inflammation in response to an insult at the respiratory mucosa render the host more susceptible to infections by Lm and possibly other pathogens that access the oral mucosa.

Sorting nexin 5 mediates virus-induced autophagy and immunity.

Autophagy, a process of degradation that occurs via the lysosomal pathway, has an essential role in multiple aspects of immunity, including immune system development, regulation of innate and adaptive immune and inflammatory responses, selective degradation of intracellular microorganisms, and host protection against infectious diseases1,2. Autophagy is known to be induced by stimuli such as nutrient deprivation and suppression of mTOR, but little is known about how autophagosomal biogenesis is initiated in mammalian cells in response to viral infection. Here, using genome-wide short interfering RNA screens, we find that the endosomal protein sorting nexin 5 (SNX5)3,4 is essential for virus-induced, but not for basal, stress- or endosome-induced, autophagy. We show that SNX5 deletion increases cellular susceptibility to viral infection in vitro, and that Snx5 knockout in mice enhances lethality after infection with several human viruses. Mechanistically, SNX5 interacts with beclin 1 and ATG14-containing class III phosphatidylinositol-3-kinase (PI3KC3) complex 1 (PI3KC3-C1), increases the lipid kinase activity of purified PI3KC3-C1, and is required for endosomal generation of phosphatidylinositol-3-phosphate (PtdIns(3)P) and recruitment of the PtdIns(3)P-binding protein WIPI2 to virion-containing endosomes. These findings identify a context- and organelle-specific mechanism-SNX5-dependent PI3KC3-C1 activation at endosomes-for initiation of autophagy during viral infection.

Utility of entomological indices for predicting transmission of dengue virus: secondary analysis of data from the Camino Verde trial in Mexico and Nicaragua.

Dengue vector entomological indices are widely used to monitor vector density and disease control activities. But the value of these indices as predictors of dengue infection is not established. We used data from the impact assessment of a trial of community mobilization for dengue prevention (Camino Verde) to examine the associations between vector indices and evidence of dengue infection and their value for predicting dengue infection levels. In 150 clusters in Mexico and Nicaragua, two entomological surveys, three months apart, allowed calculation of the mean Container Index, Breteau index, Pupae per Household Index, and Pupae per Container Index across the two surveys. We measured recent dengue virus infection in children, indicated by a doubling of dengue antibodies in paired saliva samples over the three-month period. We examined the associations between each of the vector indices and evidence of dengue infection at household level and at cluster level, accounting for trial intervention status. To examine the predictive value for dengue infection, we constructed receiver operating characteristic (ROC) curves at household and cluster level, considering the four vector indices as continuous variables, and calculated the positive and negative likelihood ratios for different levels of the indices. None of the vector indices was associated with recent dengue infection at household level. The Breteau Index was associated with recent infection at cluster level (Odds ratio 1.36, 95% confidence interval 1.14-1.61). The ROC curve confirmed the weak predictive value for dengue infection of the Breteau Index at cluster level. Other indices showed no predictive value. Conventional vector indices were not useful in predicting dengue infection in Mexico and Nicaragua. The findings are compatible with the idea of sources of infection outside the household which were tackled by community action in the Camino Verde trial.

IL-10-producing NK cells exacerbate sublethal Streptococcus pneumoniae infection in the lung.

Lung inflammation is tightly controlled to balance microbial clearance with the tissue damage that accompanies this response. Bacterial pathogens including Streptococcus pneumoniae (S. pneumoniae) modulate immune regulation by promoting secretion of the anti-inflammatory cytokine IL-10. The important cellular sources of IL-10 that impact protection against different bacterial infections are not well characterized. We find that S. pneumoniaeactivates IL-10 secretion from natural killer (NK) cells in the lung, which restrict host protection in a mouse model of sublethal infection. Direct transfer of wild-type NK cells into the lungs of IL-10-deficient mice drives bacterial expansion, identifying NK cells as a critical source of IL-10 promoting S. pneumoniae infection. The S. pneumoniae virulence protein Spr1875 was found to elicit NK cell IL-10 production in purified cells and in the lungs of live animals. These findings reveal therapeutic targets to combat bacterial-driven immune regulation in the lung.

Factors Associated with Chikungunya Relapse in Acapulco, Mexico: A Cross-Sectional Study.

Objective: To estimate the occurrence of self-reported chikungunya relapse and identify associated factors. Materials and Methods: A cross-sectional study in December 2015 included 1305 homes in eight urban clusters considered representative of Acapulco in southern Mexico. Administered questionnaires collated information on 5870 individuals, including sociodemographic variables, a history of chronic conditions, and the self-reporting of chikungunya. Bivariate and multivariate analyses relied on a cluster-adjusted Mantel-Haenszel procedure to identify the factors associated with chikungunya and its relapse. Results: Some 66% (3531/5870) of the population reported suffering chikungunya and 31.1% (1098/3531) reported a relapse. Factors associated with relapse included the severity of the chikungunya case (odds ratio [OR]: 3.35; clusters adjusted 95% confidence interval [95% CIca]: 3.16-3.55); history of arthralgia (OR: 2.96; 95% CIca: 2.27-3.86); age 30 years or older (OR: 1.85; 95% CIca: 1.72-1.98); female (OR: 1.64; 95% CIca: 1.42-1.90); and higher education households (OR: 1.18; 95% CIca: 1.11-1.27). Conclusions: The high occurrence of chikungunya and its relapse are a public health problem. The factors associated with relapse do not immediately suggest specific prevention strategies but emphasize the dire need for effective approaches to vector control.

Acute Flaccid Myelitis Among Hospitalized Children in Texas, 2016.

BACKGROUND: Acute flaccid myelitis is characterized by acute-onset flaccid limb weakness with predominantly gray matter lesions in the spinal cord spanning one or more segments. Rates of full recovery are poor, and there is no standard treatment or definitive cause. METHODS: This is a retrospective review of children diagnosed with acute flaccid myelitis in Texas during 2016. Patients were identified through a Texas collaborative of six hospitals in four major metropolitan areas. Data abstraction included health history, illness presentation, medical treatments, laboratory studies, imaging data, recovery, and ability to perform activities of daily living up to approximately two years from illness onset. RESULTS: Among all sites, 21 patients met inclusion criteria. Treatments varied with the most common being intravenous immunoglobulin, high-dose methylprednisolone, and plasmapheresis. No differences were seen in response to medical treatments. A potential etiology was found in 12 (57%) cases, including four with enterovirus D68. Five cases recovered fully. Of the 16 patients without full recovery, abilities ranged from (1) able to perform all activities of daily living for age independently (n = 5), (2) mild deficits (n = 5), and (3) substantial reliance on caregivers for activities of daily living (n = 6). CONCLUSION: Many reports describe symptoms and outcomes of acute flaccid myelitis, but limited data are available on long-term functional outcomes. We were unable to make a strong case for any single cause or treatment modality. Fortunately, the majority of patients (15, 71%) were able to perform activities of daily living with complete independence or only mild deficits.

Inflammation as a Modulator of Host Susceptibility to Pulmonary Influenza, Pneumococcal, and Co-Infections.

Bacterial and viral pathogens are predominant causes of pulmonary infections and complications. Morbidity and mortality from these infections is increased in populations that include the elderly, infants, and individuals with genetic disorders such as Down syndrome. Immune senescence, concurrent infections, and other immune alterations occur in these susceptible populations, but the underlying mechanisms that dictate increased susceptibility to lung infections are not fully defined. Here, we review unique features of the lung as a mucosal epithelial tissue and aspects of inflammatory and immune responses in model pulmonary infections and co-infections by influenza virus and Streptococcus pneumoniae. In these models, lung inflammatory responses are a double-edged sword: recruitment of immune effectors is essential to eliminate bacteria and virus-infected cells, but inflammatory cytokines drive changes in the lung conducive to increased pathogen replication. Excessive accumulation of inflammatory cells also hinders lung function, possibly causing death of the host. Some animal studies have found that targeting host modulators of lung inflammatory responses has therapeutic or prophylactic effects in these infection and co-infection models. However, conflicting results from other studies suggest microbiota, sequence of colonization, or other unappreciated aspects of lung biology also play important roles in the outcome of infections. Regardless, a predisposition to excessive or aberrant inflammatory responses occurs in susceptible human populations. Hence, in appropriate contexts, modulation of inflammatory responses may prove effective for reducing the frequency or severity of pulmonary infections. However, there remain limitations in our understanding of how this might best be achieved-particularly in diverse human populations.

Social capital is associated with lower mosquito vector indices: secondary analysis from a cluster randomised controlled trial of community mobilisation for dengue prevention in Mexico.

BACKGROUND: Control of the Aedes aegypti mosquito is central to reducing the risk of dengue, zika, chikungunya, and yellow fever. Randomised controlled trials, including the Camino Verde trial in Mexico and Nicaragua, demonstrate the convincing impact of community mobilisation interventions on vector indices. These interventions might work through building social capital but little is known about the relationship between social capital and vector indices. METHODS: A secondary analysis used data collected from 45 intervention clusters and 45 control clusters in the impact survey of the Mexican arm of the Camino Verde cluster randomised controlled trial. Factor analysis combined responses to questions about aspects of social capital to create a social capital index with four constructs, their weighted averages then combined into a single scale. We categorised households as having high or low social capital based on their score on this scale. We examined associations between social capital and larval and pupal vector indices, taking account of the effects of other variables in a multivariate analysis. We report associations as odds ratios and 95% confidence intervals. RESULTS: The four social capital constructs were involvement, participation, investment, and communication. Among the 10,112 households, those in rural communities were much more likely to have a high social capital score (OR 4.51, 95% CIca 3.26-6.26). Households in intervention sites had higher social capital, although the association was not significant at the 5% level. Households with high social capital were more likely to be negative for larvae or pupae (OR 1.38, 95% CIca 1.12-1.69) and for pupae specifically (OR 1.37, 95% CIca 1.08-1.74). There was interaction between intervention status and social capital; in multivariate analysis, a combined variable of intervention/high social capital remained associated with larvae or pupae (ORa l.56, 95% CIca 1.19-2.04) and with pupae specifically (ORa 1.65, 95% CIca 1.20-2.28). CONCLUSION: This is the first report of an association of high social capital with low vector indices. Our findings support the idea that the Camino Verde community mobilisation intervention worked partly through an interaction with social capital. Understanding such interactions may help to maximise the impact of future community mobilisation interventions.

Salud mental y su relacion con las caracteristicas biosociodemograficas en pacientes hemodializados / Saúde mental e sua relação com as características biosociodemográficas em pacientes hemodiados / Mental health and its relationship with biosociodemographic characteristics in hemodialysed patients

Resumen:La Enfermedad renal crónica terminal es considerada una pandemia a nivel mundial. En Chile un 32% de los recursos económicos en salud son destinados a su tratamiento, siendo la hemodiálisis la terapia, más utilizada en estos usuarios. Esta patología modifica todo el equilibrio de la persona, sometiéndola a diversos factores estresantes y provocándole alteraciones en el ámbito físico, psicológico y social, repercutiendo directamente en la salud mental de estos usuarios. El objetivo de esta investigación fue identificar la salud mental y su relación con las características biosociodemográficas en los pacientes hemodializados en una unidad de cuidado en Talcahuano, Chile. Se realizó un estudio cuantitativo descriptivo, correlacional y transversal. Los datos se recolectaron a través de una entrevista. El instrumento utilizado fue la Escala de Golberg para medir salud mental más variables biosociodemográficas. Los resultados obtenidos mostraron que: de un total de 53 pacientes, un 58,5% presentó ausencia de psicopatología, 26,4% presencia y el 15,1% sospecha; un 56,6% varones y el 44,4% mujeres, un 62,3% se encontraba en pareja, un 50,9 % poseía estudios de nivel medio, el 83% se encontraban pensionado, la media del tiempo en hemodiálisis fue de 94,2 meses. La presencia de diabetes mellitus se relacionó con una mayor incidencia de sospecha psicopatología. Este estudió permitió concluir que, la sospecha y/o presencia de psicopatología se relacionó con edad avanzada, sexo femenino, ingresos económicos bajos, mayor tiempo en hemodiálisis, estar pensionado y padecer diabetes. La ausencia se relacionó con mayor nivel educacional y trabajo remunerado.

Resumo:A doença renal crônica terminal é considerada uma pandemia em todo o mundo. No Chile, uns 32% dos recursos econômicos em saúde são destinados ao seu tratamento, sendo a hemodiálise a terapia mais utilizadas nesses usuários. Essa patologia modifica todo o equilíbrio da pessoa, submetendo-a a diversos fatores extressantes e provocando alterações no estado físico, psicológico e social, repercutindo diretamente na saúde mental desses usuários. O objetivo desta pesquisa foi identificar a saúde mental e sua relação com as características biosociodemográficas em pacientes com hemodiálise, da Unidade Crônica do Hospital Las Higueras, Talcahuano. Foi realizado um estudo quantitativo, descritivo, correlacional e transversal. Os dados foram coletados por meio de entrevista. O instrumento utilizado foi a Escala de Golberg para medir a saúde mental mais variáveis ​​biosociodemográficas. Os resultados obtidos mostraram que: de um total de 53 pacientes, 58,5% apresentavam ausência de psicopatologia, 26,4% presença e 15,1% suspeita; 56,6% homens e 44,4% mulheres, 62,3% se encontraram em casais, uns 50,9% tinham estudos de nível médio, 83% eram aposentados, o tempo médio em hemodiálise foi de 94,2 meses. A presença de diabetes mellitus associou-se a maior incidência de suspeita de psicopatologia. Este estudo permitiu concluir que a suspeita e / ou presença de psicopatologia estaba relacionado com a idade avançada, sexo feminino, solteiro, renda econômica baixa, maior tempo em hemodiálise, estar aposentado e portador de diabetes. A ausência esteve relacionada ao maior nível de escolaridade e trabalho remunerado.

Abstract:End-stage renal disease is considered a pandemic worldwide. In Chile 32% of the economic resources in health are destined to its treatment, being the hemodialisys the most common treatment in those patients. This pathology modifies the entire balance of the person, subjecting it to various stressors and causing alterations in the physical, psychological and social behaviors, directly impacting the mental health of patients. The objective of this research was to identify mental health and its relationship with biosociodemographic characteristics in hemodialysis patients, from the Chronic Unit at Hospital Las Higueras, Talcahuano. A descriptive, correlational and transversal quantitative study was carried out. The data was collected through an interview. The instrument used was the Golberg Scale to measure mental health plus biosociodemographic variables. Out of 53 participants, 58.5% presented absence of psychopathology, 26.4% presence and 15.1% suspicion. There were 56.6% men and 44.4% women, 60.3% were un a relationship, 50.9% had medium level formal studies, 83% were pensioned, and the average time on hemodialysis was 94.2 months. It was also found that the presence of diabetes mellitus was associated with a higher incidence of suspected psychopathology. Therefore, this study allowed us to conclude that the suspicion and / or presence of psychopathology was related to advanced age, female gender, low economic income, longer time on hemodialysis, being pensioned and suffering from diabetes. The absence was related to a higher educational level and well paid jobs.

Bacterial Stabilization of a Panel of Picornaviruses.

Several viruses encounter various bacterial species within the host and in the environment. Despite these close encounters, the effects of bacteria on picornaviruses are not completely understood. Previous work determined that poliovirus (PV), an enteric virus, has enhanced virion stability when exposed to bacteria or bacterial surface polysaccharides such as lipopolysaccharide. Virion stabilization by bacteria may be important for interhost transmission, since a mutant PV with reduced bacterial binding had a fecal-oral transmission defect in mice. Therefore, we investigated whether bacteria broadly enhance stability of picornaviruses from three different genera: Enterovirus (PV and coxsackievirus B3 [CVB3]), Kobuvirus (Aichi virus), and Cardiovirus (mengovirus). Furthermore, to delineate strain-specific effects, we examined two strains of CVB3 and a PV mutant with enhanced thermal stability. We determined that specific bacterial strains enhance thermal stability of PV and CVB3, while mengovirus and Aichi virus are stable at high temperatures in the absence of bacteria. Additionally, we determined that bacteria or lipopolysaccharide can stabilize PV, CVB3, Aichi virus, and mengovirus during exposure to bleach. These effects are likely mediated through direct interactions with bacteria, since viruses bound to bacteria in a pulldown assay. Overall, this work reveals shared and distinct effects of bacteria on a panel of picornaviruses.IMPORTANCE Recent studies have shown that bacteria promote infection and stabilization of poliovirus particles, but the breadth of these effects on other members of the Picornaviridae family is unknown. Here, we compared the effects of bacteria on four distinct members of the Picornaviridae family. We found that bacteria reduced inactivation of all of the viruses during bleach treatment, but not all viral strains were stabilized by bacteria during heat treatment. Overall, our data provide insight into how bacteria play differential roles in picornavirus stability.

Impact of Antibiotic Therapy in the Microbiological Yield of Healthcare-Associated Ventriculitis and Meningitis.

The impact of antibiotic therapy on the diagnosis of healthcare-associated ventriculitis and meningitis (HCAVM) is unknown. Antibiotics were administered before obtaining cerebrospinal fluid (CSF) in 217 out of 326 (66%) patients with HCAVM, and they impacted the sensitivity of the cerebrospinal fluid Gram stain and culture (P ≤ .004).

Strength in numbers: Mechanisms of viral co-infection.

RNA virus populations are diverse due to a variety of factors, including lack of proofreading of the viral RNA-dependent RNA polymerase. These diverse viral populations include defective viruses incapable of productive infection. Recent studies have determined the existence of several modes of viral transmission outside of canonical pathways, including en bloc transmission of multiple viruses into a single host cell via membrane vesicles. Additionally, it has recently been determined that viral aggregation and bacteria can facilitate the delivery of multiple viruses to a single cell. Co-infection of RNA viruses is important since it has the potential to enhance viral fitness. Furthermore, through complementation and recombination, co-infection could potentially promote "resurrection" of otherwise defective viral genomes and has the potential to expand viral diversity.

Identification and Characterization of a Poliovirus Capsid Mutant with Enhanced Thermal Stability.

Enteric viruses, including poliovirus, are spread by the fecal-oral route. In order to persist and transmit to a new host, enteric virus particles must remain stable once they are in the environment. Environmental stressors such as heat and disinfectants can inactivate virus particles and prevent viral transmission. It has been previously demonstrated that bacteria or bacterial surface glycans can enhance poliovirus virion stability and limit inactivation from heat or bleach. While investigating the mechanisms underlying bacterially enhanced virion thermal stability, we identified and characterized a poliovirus (PV) mutant with increased resistance to heat inactivation. The M132V mutant harbors a single amino acid change in the VP1 capsid coding that is sufficient to confer heat resistance but not bleach resistance. Although the M132V virus was stable in the absence of bacteria or feces at most temperatures, M132V virus was stabilized by feces at very high temperatures. M132V PV had reduced specific infectivity and RNA uncoating compared with those of wild-type (WT) PV, but viral yields in HeLa cells were similar. In orally inoculated mice, M132V had a slight fitness cost since fecal titers were lower and 12.5% of fecal viruses reverted to the WT. Overall, this work sheds light on factors that influence virion stability and fitness.IMPORTANCE Viruses spread by the fecal-oral route need to maintain viability in the environment to ensure transmission. Previous work indicated that bacteria and bacterial surface polysaccharides can stabilize viral particles and enhance transmission. To explore factors that influence viral particle stability, we isolated a mutant poliovirus that is heat resistant. This mutant virus does not require feces for stability at most temperatures but can be stabilized by feces at very high temperatures. Even though the mutant virus is heat resistant, it is susceptible to inactivation by treatment with bleach. This work provides insight into how viral particles maintain infectivity in the environment.

Risk Classification for Enteroviral Infection in Children With Meningitis and Negative Gram Stain.

OBJECTIVES: Enterovirus is the most common cause of aseptic meningitis in children. This study aimed at identifying baseline variables associated with a positive cerebrospinal fluid (CSF) Enterovirus polymerase chain reaction (PCR) to aid clinicians in targeting patients who could be tested and treated as outpatients. METHODS: We performed a retrospective review of children (2 months to 17 years old) admitted to the Children's Memorial Hermann Hospital in Houston, TX, between January 2005 and December 2010 with symptoms of meningitis, CSF white cell count of greater than 5 cells/mm, and a negative CSF Gram stain, who had a CSF Enterovirus PCR. RESULTS: One hundred thirty-seven children were reviewed; median age was 4.7 (0.1-17.1) years, and 79 (58%) were male. Fifty patients (37%) had positive CSF Enterovirus PCR. Only 13 (15%) of the Enterovirus PCR-negative patients had an identifiable etiology. All patients were hospitalized. The mean hospital stay for patients with Enterovirus was 2.9 days; 88% received empiric antibiotics. Rates of antibiotic administration were not different between PCR-positive and PCR-negative groups (P > 0.05). All patients with Enterovirus had a favorable clinical outcome.A predictive model was created using 3 baseline variables independently associated with a positive Enterovirus PCR (P < 0.05): May to November presentation, CSF protein of less than 100 mg/dL, and absence of focal neurologic signs. The model classified patients into 2 risk categories for a positive Enterovirus PCR (low risk, 0% [0/17 patients]; high risk, 42% [50/120 patients]; P < 0.001). CONCLUSIONS: Our predictive model can be used to identify children for whom Enterovirus PCR testing is warranted. Such testing could avoid unnecessary hospitalization and antibiotic administration.