Risk Of Secondary Transmission Research Articles

Ebola virus disease in nonendemic countries.

The 2014 West African outbreak of Ebola virus disease was unprecedented in its scale and has resulted in transmissions outside endemic countries. Clinicians in nonendemic countries will most likely face the disease in returning travelers, either among healthcare workers, expatriates, or visiting friends and relatives. Clinical suspicion for the disease must be heightened for travelers or contacts presenting with compatible clinical syndromes, and strict infection control measures must be promptly implemented to minimize the risk of secondary transmission within healthcare settings or in the community. We present a concise review on human filoviral disease with an emphasis on issues that are pertinent to clinicians practicing in nonendemic countries.

Hepatology highlights

Hepatology highlights

Bidirectional links between HIV and intimate partner violence in pregnancy: implications for prevention of mother-to-child transmission.

IntroductionPrevention of mother-to-child transmission (PMTCT) has the potential to eliminate new HIV infections among infants. Yet in many parts of sub-Saharan Africa, PMTCT coverage remains low, leading to unacceptably high rates of morbidity among mothers and new infections among infants. Intimate partner violence (IPV) may be a structural driver of poor PMTCT uptake, but has received little attention in the literature to date.MethodsWe conducted qualitative research in three Johannesburg antenatal clinics to understand the links between IPV and HIV-related health of pregnant women. We held focus group discussions with pregnant women (n=13) alongside qualitative interviews with health care providers (n=10), district health managers (n=10) and pregnant abused women (n=5). Data were analysed in Nvivo10 using a team-based approach to thematic coding.FindingsWe found qualitative evidence of strong bidirectional links between IPV and HIV among pregnant women. HIV diagnosis during pregnancy, and subsequent partner disclosure, were noted as a common trigger of IPV. Disclosure leads to violence because it causes relationship conflict, usually related to perceived infidelity and the notion that women are “bringing” the disease into the relationship. IPV worsened HIV-related health through poor PMTCT adherence, since taking medication or accessing health services might unintentionally alert male partners of the women's HIV status. IPV also impacted on HIV-related health via mental health, as women described feeling depressed and anxious due to the violence. IPV led to secondary HIV risk as women experienced forced sex, often with little power to negotiate condom use. Pregnant women described staying silent about condom negotiation in order to stay physically safe during pregnancy.ConclusionsIPV is a crucial issue in the lives of pregnant women and has bidirectional links with HIV-related health. IPV may worsen access to PMTCT and secondary prevention behaviours, thereby posing a risk of secondary transmission. IPV should be urgently addressed in antenatal care settings to improve uptake of PMTCT and ensure that goals of maternal and child health are met in sub-Saharan African settings.

Health Care Workers’ Suggestions for Improving HIV‐Related Maternal Care in South Africa: “Listen to Us”

South Africa has the highest rate of individuals infected with HIV in the world. Women in particular are at increased risk for HIV infection and typically receive care from nurses and midwives who are on the front lines of health care policy and program implementation. The primary objective of this study was to compile and analyze suggestions generated by health care professionals on how to improve HIV-related maternal care in South Africa. This information can then be used to inform the direction of future programs across the country and beyond. Two hundred forty-nine nurses, midwives, and nursing students enrolled in a South African university completed surveys as part of this qualitative cross-sectional study. Responses were transcribed and coded by independent researchers who met frequently to discuss and come to consensus on emerging themes. Four primary strategies to improve HIV-related maternal care emerged from the data. These women's health professionals suggested improving education, increasing grassroots-level participation by government officials, improving resources, and developing strategies aimed at decreasing the risk of secondary transmission of HIV. Nurses and midwives are frontline health care professionals who are in unique positions to offer feedback on how HIV-related maternal care can be improved. The identified strategies should be integrated into future programs, and human rights implications must be examined.

Strategies and Outcomes of HIV Status Disclosure in HIV-Positive Young Women with Abuse Histories

Young women with HIV and histories of physical and/or sexual abuse in childhood may be vulnerable to difficulties with disclosure to sexual partners. Abuse in childhood is highly prevalent in HIV-positive women, and has been associated with poorer communication, low assertiveness, low self worth, and increased risk for sexual and other risk behaviors that increase the risk of secondary transmission of HIV. HIV disclosure may be an important link between abuse and sexual risk behaviors. Qualitative interviews with 40 HIV-positive young women with childhood physical and/or sexual abuse were conducted; some women had also experienced adult victimization. Results suggest that HIV-positive women with abuse histories use a host of strategies to deal with disclosure of HIV status, including delaying disclosure, assessing hypothetical responses of partners, and determining appropriate stages in a relationship to disclose. Stigma was an important theme related to disclosure. We discuss how these disclosure processes impact sexual behavior and relationships and discuss intervention opportunities based on our findings.

Historic aspects of human susceptibility to leprosy and the risk of conjugal transmission

Estimates of genetic susceptibility to leprosy were made in the past from observational reports in familial settings using descriptive epidemiologic data. Risk of conjugal transmission of leprosy (from one spouse to another) has been estimated between 1-10% and is thought to occur in 3-5% of spouses exposed to untreated lepromatous disease in the partner. Risk of secondary transmission is presumed higher in other family members than for the conjugal partner. This belief has become dogma to many leprologists who may no longer know the basis for this estimation. This article reviews the historic epidemiologic descriptions of risk for leprosy transmission in married couples compared to other family members. Although uncommon, conjugal leprosy occurs and at higher rates in populations with traditional familial intermarriage and consanguinity.

Secondary transmissions during the outbreak of Shiga toxin-producing Escherichia coli O104 in Hesse, Germany, 2011

During the recent outbreak of Shiga toxin-producing Escherichia coli (STEC) O104:H4 in Germany most cases notified in the State of Hesse (6 million inhabitants) were linked to satellite clusters or had travelled to the outbreak area in northern Germany. Intensified surveillance was introduced to rapidly identify cases not linked to known clusters or cases and thus to obtain timely information on possible further contaminated vehicles distributed in Hesse, as well to describe the risk of secondary transmission among known cases. As of 2 August 2011* [corrected], 56 cases of haemolytic uraemic syndrome (HUS) including two fatal cases, and 124 cases of STEC gastroenteritis meeting the national case definitions have been reported in Hesse. Among the 55 HUS and 81 STEC gastroenteritis cases thatmet the outbreak case definition, one HUS case and eight STEC gastroenteritis cases may have acquired their infection through secondary transmission. They include six possible transmissions within the family, two possible nosocomial and one possible laboratory transmission. Our results do not suggest an increased transmissibility of the outbreak strain compared to what is already known about E. coli O157 and other STEC serotypes.

Transmission of Varicella Vaccine Virus, Japan

Transmission of Varicella Vaccine Virus, Japan

Coping Strategies and Patterns of Alcohol and Drug Use among HIV-Infected Patients in the United States Southeast

Alcohol and drug use are common among HIV-infected patients and are important determinants of secondary transmission risk and medication adherence. As part of the Coping with HIV/AIDS in the Southeast (CHASE) Study, 611 HIV-infected patients were consecutively recruited from eight clinical care sites in five southeastern U.S. states in 2001-2002. We examined the distribution and predictors of alcohol and drug use in this sample with an emphasis on psychosocial predictors of use. In the prior 9 months, 27% of participants drank alcohol and 7% drank to intoxication at least weekly. The most common drugs used at least weekly were marijuana (12%) and crack (5%); 11% used a non-marijuana drug. 7% reported polysubstance use (use of multiple substances at one time) at least weekly. Injection drug use was rare (2% injected at least once in the past 9 months). There were few differences in alcohol and drug use across sociodemographic characteristics. Stronger adaptive coping strategies were the most consistent predictor of less frequent alcohol and drug use, in particular coping through action and coping through relying on religion. Stronger maladaptive coping strategies predicted greater frequency of drinking to intoxication but not other measures of alcohol and drug use. Those with more lifetime traumatic experiences also reported higher substance use. Interventions that teach adaptive coping strategies may be effective in reducing alcohol and substance use among HIV-positive persons.

In vitro amplification and detection of variant Creutzfeldt–Jakob disease PrPSc

Variant Creutzfeldt-Jakob disease (vCJD) poses a serious risk of secondary transmission and the need to detect infectivity in asymptomatic individuals is therefore of major importance. Following infection, it is assumed that minute amounts of disease-associated prion protein (PrP(Sc)) replicate by conversion of the host cellular prion protein (PrP(C)). Therefore, methods of rapidly reproducing this conversion process in vitro would be valuable tools in the development of such tests. We show that one such technique, protein misfolding cyclic amplification (PMCA), can amplify vCJD PrP(Sc) from human brain tissue, and that the degree of amplification is dependent upon the substrate PRNP codon 129 polymorphism. Both human platelets and transgenic mouse brain are shown to be suitable alternative substrate sources, and amplified PrP(Sc) can be detected using a conformation-dependent immunoassay (CDI), allowing the detection of putative proteinase K sensitive forms of PrP(Sc).

Cas de choléra d'importation en France, été 2005. A. Tarantola pour les groupes de gestion des incidents

Cholera is a bacterial infection, which causes digestive symptoms and massive diarrhoea. It may lead to dehydration and death if appropriate medical management is not rapidly initiated. Most cases of infection by choleric vibrio, however, remain symptom-free or may mimic common gastroenteritis. A review of two cases of imported cholera in France in the summer of 2005 and the community- and hospital-based investigation, which they triggered, enabled the incident management teams to assess risks of transmission. There were no secondary cases among 58 hospital contacts and 15 family contacts of the cases. Clinicians will find a discussion of possible clinical presentations and the risk of secondary transmission, in the context of progressing epidemics in countries, which have maintained close ties with France.

Viral load and outcome in SARS infection: The role of personal protective equipment in the emergency department

This study was conducted to evaluate the effectiveness of personal protective equipment (PPE) against severe acute respiratory syndrome (SARS). Sixteen patients in a SARS cluster, including 4 health care workers (HCWs) and 12 non-HCWs were studied. We compared the initial viral load by nasopharyngeal swabs, clinical progression, and outcome of this cluster. The HCWs had a lower viral load. The non-HCWs had a higher mean C-reactive protein, lower oxygen saturation, and a higher incidence of intubation and death. Secondary household transmission developed in three of the non-HCWs’ families. One month after discharge, non-HCWs had more signs of fibrosis on high resolution computed tomography (HRCT) scan and an impaired pulmonary function test. Although most of the PPE do not confer absolute protection against SARS, it seems that they may lower exposure to the virus, leading to a lower risk of secondary transmission, and be associated with relatively mild disease and a better early outcome.

Management of patients infected with airborne-spread diseases: An algorithm for infection control professionals

BackgroundMany US hospitals lack the capacity to house safely a surge of potentially infectious patients, increasing the risk of secondary transmission. Respiratory protection and negative-pressure rooms are needed to prevent transmission of airborne-spread diseases, but US hospitals lack available and/or properly functioning negative-pressure rooms. Creating new rooms or retrofitting existing facilities is time-consuming and expensive.MethodsSafe methods of managing patients with airborne-spread diseases and establishing temporary negative-pressure and/or protective environments were determined by a literature review. Relevant data were analyzed and synthesized to generate a response algorithm.ResultsIdeal patient management and placement guidelines, including instructions for choosing respiratory protection and creating temporary negative-pressure or other protective environments, were delineated. Findings were summarized in a treatment algorithm.ConclusionThe threat of bioterrorism and emerging infections increases health care's need for negative-pressure and/or protective environments. The algorithm outlines appropriate response steps to decrease transmission risk until an ideal protective environment can be utilized. Using this algorithm will prepare infection control professionals to respond more effectively during a surge of potentially infectious patients following a bioterrorism attack or emerging infectious disease outbreak.

Processing of Whole Femoral Head Allografts: Validation Methodology for the Reliable Removal of Nucleated Cells, Lipid and Soluble Proteins Using a Multi-step Washing Procedure

Following the major outbreak of BSE in the United Kingdom in the mid 1980's and the first reported cases of the human disease equivalent, vCJD, in 1996 a number of measures were taken to reduce the risk of secondary transmission of vCJD by blood or surgical instruments. Two cases of probable transmission of vCJD by blood components have now been reported. The Department of Health has recently undertaken a vCJD risk analysis for bone. Although significant uncertainties still exist in the assumptions on which the assessment is based, a few important recommendations were made. These include a recommendation that bone should be processed to remove blood and marrow and that pooling of donations is never advantageous. This study aimed to establish a method of processing whole femoral heads using disposable equipment, with the purpose of removing as much of the marrow components as possible. We are able to remove 98.2% (range 94.5-99.9%) of the nucleated cells and 98.7% (range 97.8-99.4%) of the soluble protein content from within an intact femoral head. This work confirms that the majority of blood and marrow components can be removed without the need for morselising the bone prior to washing.

Le nouveau variant de la maladie de Creutzfeldt-Jakob en France : estimation du nombre de cas attribuables à un séjour dans les îles britanniques entre 1980 et 1995

The outbreak of variant Creutzfeldt-Jakob disease (vCJD) cases rose serious concerns about secondary transmission of the disease, particularly through blood transfusion. Protective measures leading to the exclusion of potentially infectious blood donors were settled: in France, donors who had stayed more than one year in the UK were excluded. In this work, which was part of a larger study aiming to estimate the French epidemic of vCJD, the number of vCJD cases who were infected during a trip to the UK was estimated. Those estimates may notably enable the assessment of such exclusion measures. The particular age-related structure in vCJD cases is taken into account in our simulations considering birth cohorts in the population. The total French exposure is simulated assuming the main source of infection to be dietary through consumption of mechanically recovered meat (MRM) manufactured from British bovine carcasses. Then, using a "back calculation" algorithm, all infected individuals required to produce a consistent epidemic (6 vCJD cases in 2003) was simulated. This study was exclusively focused on the part of the exposure linked to trips (beef MRM consumed in the UK while traveling) and on cases resulting from this exposure. The influence of exposure linked to trips to the UK was greater in the youngest cohort (6.3% of the total exposure) while it only accounted for 3.3% and 1% in the 1939-69 and in the pre-1939 birth cohorts respectively. Overall, exposure resulting from trips in the UK can be neglected with regards to the exposure linked to the consumption of MRM produced in France from British bovine carcasses. Consequently, French vCJD cases that would have been infected in the UK are very unlikely to occur (median: 0 case, IC 95%: (0-2)). Nevertheless, if such cases occur, they would probably occur in subjects born after 1969 and their onset would take place before 2010. Thus, unlike the situation in BSE-free countries, the causal relationship between travel in the UK and occurrence of vCJD cases cannot be underlined in France, as trips only account for a small part of the French exposure. Since trips in the UK slightly contribute to the overall French exposure, excluding people who travelled in the UK from blood donation would not influence the risk of secondary transmission.

The effect of semipermeable dressings on smallpox vaccine site evolution

Many hospital systems in the United States are contemplating the implementation of a smallpox vaccination program. The Centers for Disease Control and Prevention and other organizations recommend use of occlusive dressings over the vaccination site of health care workers in contact with patients. Minimal data are available on the impact of an occlusive dressing on the evolution of the vaccinia inoculation site. We conducted a prospective observational study in which subjects were instructed to cover their vaccination site with either a semipermeable dressing over gauze or gauze alone. We recorded the duration of semipermeable dressing use and parameters pertaining to vaccination site evolution, to include time until scab separation. The increased use of a semipermeable dressing is associated with increased time until scab separation (n = 41, r =.48, P =.001 by regression analysis). This analysis predicts a 9-day difference in time until scab separation between patients that wore semipermeable dressings 100% of the time versus not at all. No significant correlation was observed between semipermeable dressing use and size of maximum erythema, time until maximum erythema, size of erythema on day 6 or 8, nor time until pustule formation. Semipermeable dressing use appears to prolong the time until scab separation and possibly the duration of infectivity and risk of secondary transmission. Health care organizations may wish to consider this information when instituting a smallpox vaccination program.

Imported Lassa fever in Germany: surveillance and management of contact persons.

This study sought to assess the risk of secondary transmission after import of Lassa fever into Europe. A total of 232 persons exposed to a case of Lassa fever imported into Germany were identified. The level of exposure was determined for 157 persons (68%), and 149 (64%) were tested serologically. High-risk or close contact was reported by 30 (19%) of 157 persons. No symptomatic secondary infections were observed. However, Lassa virus-specific immunoglobulin G antibodies were detected in a serum sample obtained from a physician who examined the index patient on day 9 of illness. The physician received ribavirin prophylaxis and did not develop symptoms of Lassa fever. On the basis of these data, the contact was classified as having a probable secondary infection. The study indicates a low risk of transmission during the initial phase of symptomatic Lassa fever, even with high-risk exposures. The risk may increase with progression of disease and increasing virus load.

How contagious is vaccinia?

Smallpox vaccination carries with it well-known risks of adverse events, but problems may also arise from the risk of secondary transmission of the live virus. This review article examines what is known about the potential for nosocomial infection and for spread within families. The author also assesses the implications for vaccination policy.

Sexual risk behaviors and implications for secondary HIV transmission during and after HIV seroconversion.

To determine the potential for secondary HIV transmission among newly HIV-infected men who have sex with men (MSM) during their HIV antibody seroconversion period, and for the 12 months after seroconversion. A cohort study. Risk assessment questionnaires administered before receipt of the first positive HIV antibody result, plasma and seminal viral load measurements, and risk assessments one month and quarterly after receipt of the first HIV-positive test, and generalized estimating equation modelling techniques to analyse behavioral trends. Of 66 seroconverters, more than half reported unprotected anal intercourse (UAI) with HIV-negative or unknown-serostatus partners during seroconversion, with 27% reporting insertive UAI with an HIV-negative partner. The initial median plasma viral load was 4.6 log/ml, the median seminal viral load was 2.7 log/ml, suggesting a high level of infectiousness. Compared with risk behavior during seroconversion, UAI with HIV-negative or unknown-serostatus partners was reduced after the receipt of positive antibody results; however, a substantial proportion of participants reported high-risk behaviors for transmission for 12 months of follow-up. After learning of their HIV infection, recent seroconverters did not reduce the risk of secondary transmission by engaging in proportionally more high-risk practices with HIV-infected partners (compared with HIV-negative or unknown-serostatus partners), or engaging in proportionally more receptive compared with insertive UAI. Substantial potential exists for secondary HIV transmission during and for one year after HIV seroconversion. Receipt of an HIV-positive test is associated with a significant reduction in risk behavior, reinforcing the need to identify and counsel recently HIV-infected MSM.

Tissue distribution of protease resistant prion protein in variant Creutzfeldt-Jakob disease using a highly sensitive immunoblotting assay

Variant Creutzfeldt-Jakob disease (vCJD) has a pathogenesis distinct from other forms of human prion disease: disease-related prion protein (PrP(Sc)) is readily detectable in lymphoreticular tissues. Quantitation of risk of secondary transmission, and targeting of risk reduction strategies, is limited by lack of knowledge about relative prion titres in these and other peripheral tissues, the unknown prevalence of preclinical vCJD, and a transmission barrier which limits the sensitivity of bioassay. We aimed to improve immunoblotting methods for high sensitivity detection of PrP(Sc) to investigate the distribution of PrP(Sc) in a range of vCJD tissues. We obtained tissues at necropsy from four patients with neuropathologically confirmed vCJD and from individuals without neurological disease. Tissues were analysed by sodium phosphotungstic acid precipitation of PrP(Sc) and western blotting using high sensitivity enhanced chemiluminescence. We could reliably detect PrP(Sc) in the equivalent of 50 nL 10% vCJD brain homogenate, with a maximum limit of detection equivalent to 5 nl. PrP(Sc) could be detected in tissue homogenates when present at concentrations 10(4)-10(5) fold lower than those reported in brain. Tonsil, spleen, and lymph node were uniformly positive for PrP(Sc) at concentrations in the range of 0.1-15% of those found in brain: the highest concentrations were consistently seen in tonsil. PrP(Sc) was readily detected in the retina and proximal optic nerve of vCJD eye at levels of 2.5 and 25%, respectively of those found in brain. Other peripheral tissues studied were negative for PrP(Sc) with the exception of low concentrations in rectum, adrenal gland, and thymus from a single patient with vCJD. vCJD appendix and blood (Buffy coat fraction) were negative for PrP(Sc) at this level of assay sensitivity. We have developed a highly sensitive immunoblot method for detection of PrP(Sc) in vCJD tissues that can be used to provide an upper limit on PrP(Sc) concentrations in peripheral tissues, including blood, to inform risk assessment models. Rectal and other gastrointestinal tissues should be further investigated to assess risk of iatrogenic transmission via biopsy instruments. Ophthalmic surgical instruments used in procedures involving optic nerve and the posterior segment of the eye, in particular the retina, might represent a potential risk for iatrogenic transmission of vCJD. Tonsil is the tissue of choice for diagnostic biopsy and for population screening of surgical tissues to assess prevalence of preclinical vCJD infection within the UK and other populations.