Pet rodents and fatal lymphocytic choriomeningitis in transplant patients

In April 2005, 4 transplant recipients became ill after receiving organs infected with lymphocytic choriomeningitis virus (LCMV); 3 subsequently died. All organs came from a donor who had been exposed to a hamster infected with LCMV. The hamster was traced back through a Rhode Island pet store to a distribution center in Ohio, and more LCMV-infected hamsters were discovered in both. Rodents from the Ohio facility and its parent facility in Arkansas were tested for the same LCMV strain as the 1 involved in the transplant-associated deaths. Phylogenetic analysis of virus sequences linked the rodents from the Ohio facility to the Rhode Island pet store, the index hamster, and the transplant recipients. This report details the animal traceback and the supporting laboratory investigations.     

Interim guidance for minimizing risk for human lymphocytic choriomeningitis virus infection associated with rodents

In May 2005, CDC received reports of four organ-transplant recipients with unknown illness. All were discovered to have been infected with lymphocytic choriomeningitis virus (LCMV) via a common organ donor. Epidemiologic investigation traced the source of the virus to a pet hamster purchased by the donor from a local pet store. LCMV testing of other rodents at the pet store revealed three other LCMV-infected rodents (two hamsters and a guinea pig), supplied by a single distributor (distributor A). Preliminary laboratory testing of hamsters from distributor A has identified an infection rate of approximately 3% among the animals sampled. The facility of distributor A is under quarantine until it can be documented as free of LCMV infection. This report provides background information on LCMV and interim guidance for the public on reducing risk for LCMV infection from pet rodents.     

Independent Lineage of Lymphocytic Choriomeningitis Virus in Wood Mice (Apodemus sylvaticus), Spain

To clarify the presence of lymphocytic choriomeningitis virus (LCMV) in Spain, we examined blood and tissue specimens from 866 small mammals. LCMV RNA was detected in 3 of 694 wood mice (Apodemus sylvaticus). Phylogenetic analyses suggest that the strains constitute a new evolutionary lineage. LCMV antibodies were detected in 4 of 10 rodent species tested.     

New Perspective on the Geographic Distribution and Evolution of Lymphocytic Choriomeningitis Virus,Central Europe

Lymphocytic choriomeningitis virus (LCMV) is an Old World mammarenavirus found worldwide because of its association with the house mouse. When LCMV spills over to immunocompetent humans, the virus can cause aseptic meningitis; in immunocompromised persons, systemic infection and death can occur. Central Europe is a strategic location for the study of LCMV evolutionary history and host specificity because of the presence of a hybrid zone (genetic barrier) between 2 house mouse subspecies, Mus musculus musculus and M. musculus domesticus. We report LCMV prevalence in natural mouse populations from a Czech Republic–Germany transect and genomic characterization of 2 new LCMV variants from the Czech Republic. We demonstrate that the main division in the LCMV phylogenetic tree corresponds to mouse host subspecies and, when the virus is found in human hosts, the mouse subspecies found at the spillover location. Therefore, LCMV strains infecting humans can be predicted by the genetic structure of house mice.     

Mouse-to-human transmission of variant lymphocytic choriomeningitis virus

A case of lymphocytic choriomeningitis virus (LCMV) infection led to investigation of the reservoir. LCMV was detected in mice trapped at the patient's home, and 12 isolates were recovered. Genetic analysis showed that human and mouse LCMVs were identical and that this LCMV strain was highly divergent from previously characterized LCMV.     

鼠类感染淋巴细胞脉络丛脑膜炎病毒的RT—PCR检测与N基因序列分析

目的了解宁波市梅山口岸鼠类中淋巴细胞脉络丛脑膜炎病毒（LCMV）流行情况和基因序列特征。方法以LCMVN基因设计2对引物,采用RT—PCR方法对2012年宁波市梅山口岸捕获的鼠类样品进行LCMV检测,并对阳性样品的PCR产物进行测序及同源性和系统进化树分析。结果共检测53份鼠类样品,其中2份小家鼠样品为LCMV核酸阳性,分离的2株LCMV与国外LCMV分离株的同源性在75％~87％之间,与WHI株同源性最高（87％）并在系统发生树上属于同一组。结论证实当地鼠类中存在LCMV流行,新检测到的2株病毒与国外LCMV分离株存在一定差异。     

Brief report: Lymphocytic choriomeningitis virus transmitted through solid organ transplantation--Massachusetts, 2008

Lymphocytic choriomeningitis virus (LCMV) is a rodent-borne arenavirus found worldwide. House mice (Mus musculus) are the natural reservoir, but LCMV also can infect other wild, pet, and laboratory rodents (e.g., rats, mice, guinea pigs, and hamsters). Humans can be infected through exposure to rodent excreta. Person-to-person transmission has occurred only through maternal-fetal transmission and solid organ transplantation. LCMV infection in humans can be asymptomatic or cause a spectrum of illness ranging from isolated fever to meningitis and encephalitis. Overall case fatality is <1%. Fetal infections can result in congenital abnormalities or death. Immunosuppressed patients, such as organ transplant recipients, can develop fatal hemorrhagic fever-like disease. Transmission of LCMV and an LCMV-like arenavirus via organ transplantation has been documented in three previous clusters. Of 11 recipients described in those clusters, 10 died of multisystem organ failure, with LCMV-associated hepatitis as a prominent feature. The surviving patient was treated with ribavirin (an antiviral with in vitro activity against LCMV) and reduction of immunosuppressive therapy. On April 15, 2008, an organ procurement organization (OPO) notified CDC of severe illness in two kidney transplant recipients from a common donor; at the time of notification, one of the recipients had died. Samples from the donor and both recipients were tested at CDC; on April 22, test results revealed evidence of acute LCMV infection in the donor and both recipients. This report summarizes the results of the subsequent public health investigation.     

Diminished primary CD8 T cell response to viral infection during protein energy malnutrition in mice is due to changes in microenvironment and low numbers of viral-specific CD8 T cell precursors

Protein energy malnutrition (PEM) increases the incidence and severity of infection, causing morbidity and mortality in malnourished populations. Viral-specific cells are an important component of protective immunity. We hypothesized that reduction in the expansion of viral-specific cells and the microenvironment of the PEM host leads to increased incidence and severity of infections. We tested this hypothesis using a mouse model of lymphocytic choriomeningitis virus (LCMV) infection and an adoptive transfer system using P14 transgenic mice cells bearing T cell receptors specific for the D(b)-restricted LCMV glycoprotein 33-41 epitope. We transferred equal numbers of P14 cells from mice fed either an adequate, 18% protein or low, 0.6% protein diet into C57BL/6 mice that had been fed adequate-protein (AP) or low-protein (LP) diets for 2 wk, infected them with LCMV, and followed them 1 wk postinfection. During PEM, the expansion of primary viral-specific CD8 T cells diminished; in LP diet-fed mice, it was only 2-3% of that in the AP diet-fed mice. Furthermore, the diminished primary CD8 T cell response during PEM may in part have been due to low numbers of viral-specific CD8 T cells and an altered microenvironment.     

Identification of lymphocytic choriomeningitis mammarenavirus in house mouse (Mus musculus,Rodentia) in French Guiana

Thirty-seven house mice (Mus musculus, Rodentia) caught in different localities in French Guiana were screened to investigate the presence of lymphocytic choriomeningitis mammarenavirus (LCMV). Two animals trapped in an urban area were found positive, hosting a new strain of LCMV, that we tentatively named LCMV “Comou”. The complete sequence was determined using a metagenomic approach. Phylogenetic analyses revealed that this strain is related to genetic lineage I composed of strains inducing severe disease in humans. These results emphasize the need for active surveillance in humans as well as in house mouse populations, which is a rather common rodent in French Guianese cities and settlements.     

Survey of lymphocytic choriomeningitis virus diagnosis and testing--Connecticut, 2005

Lymphocytic choriomeningitis virus (LCMV) is a rodent borne virus that can be transmitted to humans through exposure to rodent urine, feces, saliva, or blood. LCMV infection is often asymptomatic or mild but can cause aseptic meningitis, encephalitis, life-threatening infections in immunosuppressed persons, and severe congenital defects . In May 2005, LCMV was implicated in the deaths of three organ transplant recipients who had received organs from a common donor who had likely been infected from a pet rodent. In August 2005, the Connecticut Department of Public Health conducted surveys of hospital laboratories and infectious disease (ID) physicians in Connecticut to determine recent incidence of confirmed LCMV infection, the level of awareness of LCMV, and the frequency of LCMV testing. This report summarizes the results of those surveys, which indicate that awareness of LCMV is high among ID physicians; however, testing for LCMV is infrequent, and ID physicians might not be aware of the need to consider LCMV among the most susceptible populations even when a history of rodent contact is not initially evident. In part because of these findings, LCMV infection is now a physician- and laboratory-reportable disease in Connecticut. More systematic efforts are needed to determine the frequency of LCMV infection and to monitor for pet rodent infection.     

Lymphocytic Choriomeningitis Virus Infections and Seroprevalence,Southern Iraq

Acute febrile neurological infection cases in southern Iraq (N = 212) were screened for lymphocytic choriomeningitis virus (LCMV). Two LCMV IgM–positive serum samples and 2 cerebrospinal fluid samples with phylogenetically distinct LCMV strains were found. The overall LCMV seroprevalence was 8.8%. LCMV infections are common and associated with acute neurological disease in Iraq.     

Induction of protective antiviral cytotoxic T cells by a tubular structure capable of carrying large foreign sequences

Bluetongue virus (BTV) produces large numbers of tubules during infection which are formed by a single virus coded non-structural protein, NS1. The NS1 protein has been fused with full length green fluorescent protein (GFP) and was shown to retain the capacity to form tubules when expressed in heterologous expression systems. Moreover, recombinant purified chimeric tubules were demonstrated to be internalized by macrophages and dendritic cells. The ability of such chimeric tubules to induce protective cytotoxic T lymphocytes (CTL) responses has been assessed by generating chimeric tubules carrying a single CD8(+) T cell epitope from the lymphocytic choriomeningitis virus (LCMV) nucleoprotein. These chimeric tubules were recognized by MHC class I restricted T cell hybridoma in vitro and induced in vivo strong CD8(+) class I-restricted CTL responses in immunized mice. Further, the immunized mice were protected when challenged with a lethal dose of LCMV. This is the first study that demonstrates that the virus derived tubules synthesized by a recombinant non-structural protein carrying a single viral CTL epitope could induce protective immunity against a lethal viral challenge. Since recombinant tubules carrying large inserts can be purified at a large quantity from insect cells, they have potential to develop as safe multi-CTL vaccine delivery systems.     

Peptide vaccination using nonionic block copolymers induces protective anti-viral CTL responses.

High molecular weight nonionic block copolymers have been developed as vaccine adjuvants. We employed these adjuvants in water-in-oil emulsion and multiple emulsion formulations with a synthetic peptide-based antigen vaccine to test their ability to prime anti-viral CD8(+) T cell responses. Vaccines were made using the H-2(d)-restricted immunodominant peptide from lymphocytic choriomeningitis virus (LCMV), NP118-126, and administered to BALB/c ByJ (H-2(d)) mice. Peptide-containing emulsions were able to induce NP118-126 specific CTL and IFN-gamma secreting CD8(+) T cells in the vaccinated mice and these responses were maintained for at least 90 days post immunization. At all times, the responses induced by the copolymer formulations were equal to, or better than, formulations based on incomplete Freund's adjuvant (IFA). In addition, the responses induced by prophylactic vaccination using the multiple emulsion formulation resulted in accelerated viral clearance following infection with a strain of LCMV (clone 13) that causes a persistent infection in na?ve adult mice. These results indicate that peptide vaccination using a formulation based on high molecular weight nonionic block copolymer in a simple water-in-oil or a multiple emulsion format can induce virus-specific CD8(+) T cell responses and confer protection sufficient enough to prevent the establishment of a persistent infection.     

High Diversity and Ancient Common Ancestry of Lymphocytic Choriomeningitis Virus

Lymphocytic choriomeningitis virus (LCMV) is the prototype of the family Arenaviridae. LCMV can be associated with severe disease in humans, and its global distribution reflects the broad dispersion of the primary rodent reservoir, the house mouse (Mus musculus). Recent interest in the natural history of the virus has been stimulated by increasing recognition of LCMV infections during pregnancy, and in clusters of LCMV-associated fatal illness among tissue transplant recipients. Despite its public health importance, little is known regarding the genetic diversity or distribution of virus variants. Genomic analysis of 29 LCMV strains collected from a variety of geographic and temporal sources showed these viruses to be highly diverse. Several distinct lineages exist, but there is little correlation with time or place of isolation. Bayesian analysis estimates the most recent common ancestor to be 1,000–5,000 years old, and this long history is consistent with complex phylogeographic relationships of the extant virus isolates.     

Effect of the deletion of US2 and US3 from herpes simplex virus type 2 on immune responses in the murine vagina following intravaginal infection

We investigated the effects of US2 and US3 deficiencies of herpes simplex virus type 2 (HSV-2) on host immunity in a murine model of genital herpes infection. Viral clearance from the vaginal mucosa was more rapid in mice infected with a US3-deficient mutant L1BR1 as compared with a wild-type 186 or YY2 (US2-deficient mutant) infection, although there was no significant difference among them in initial growth in the early stage of infection. Flow cytometric studies revealed that the number of vaginal mononuclear cells in L1BR1-infected mice was significantly greater than that in 186- or YY2-infected mice. Dendritic cells, macrophages and T cells were induced more rapidly and in greater numbers within the vaginas of L1BR1-infected mice. Moreover, the levels of IL-12 and IFN-gamma increased in L1BR1-infected mice over levels in 186-infected mice. These results indicate that a US3 deficiency alters the induction of the host immune response; therefore, the inactivation of US3 may be a promising strategy in the development of novel vaccines for genital herpes.     

The economic burden of inpatient paediatric care in Kenya: household and provider costs for treatment of pneumonia, malaria and meningitis

Background

Knowledge of treatment cost is essential in assessing cost effectiveness in healthcare. Evidence of the potential impact of implementing available interventions against childhood illnesses in developing countries challenges us to define the costs of treating these diseases. The purpose of this study is to describe the total costs associated with treatment of pneumonia, malaria and meningitis in children less than five years in seven Kenyan hospitals.

Methods

Patient resource use data were obtained from largely prospective evaluation of medical records and household expenditure during illness was collected from interviews with caretakers. The estimates for costs per bed day were based on published data. A sensitivity analysis was conducted using WHO-CHOICE values for costs per bed day.

Results

Treatment costs for 572 children (pneumonia = 205, malaria = 211, meningitis = 102 and mixed diagnoses = 54) and household expenditure for 390 households were analysed. From the provider perspective the mean cost per admission at the national hospital was US $95.58 for malaria, US $177.14 for pneumonia and US $284.64 for meningitis. In the public regional or district hospitals the mean cost per child treated ranged from US $47.19 to US $81.84 for malaria and US $54.06 to US $99.26 for pneumonia. The corresponding treatment costs in the mission hospitals were between US $43.23 to US $88.18 for malaria and US $ 43.36 to US $142.22 for pneumonia. Meningitis was treated for US $ 189.41 at the regional hospital and US $ 201.59 at one mission hospital. The total treatment cost estimates were sensitive to changes in the source of bed day costs. The median treatment related household payments within quintiles defined by total household expenditure differed by type of facility visited. Public hospitals recovered up to 40% of provider costs through user charges while mission facilities recovered 44% to 100% of costs.

Conclusion

Treatments cost for inpatient malaria, pneumonia and meningitis vary by facility type, with mission and tertiary referral facilities being more expensive compared to primary referral. Households of sick children contribute significantly towards provider cost through payment of user fees. These findings could be used in cost effectiveness analysis of health interventions.     

Induction of specific CD8+ memory T cells and long lasting protection following immunization with Salmonella typhimurium expressing a lymphocytic choriomeningitis MHC class I-restricted epitope.

Numerous studies have shown the potential of Salmonella typhimurium as a vector for delivery of heterologous proteins for vaccination against other pathogens. Earlier studies showed that the inefficient elicitation of MHC class I-restricted responses could limit the use of S. typhimurium as a heterologous antigen delivery vector for vaccination. We recently developed an approach to overcome this limitation by using a bacterial-encoded specialized protein secretion system, termed type III, to deliver proteins into the class I antigen presenting pathways. Thus, peptides of interest fused to proteins bearing the type III secretion signal, which can elicit protective CTL responses. Because protective immunity is usually assessed a few weeks after vaccination, there is a paucity of information regarding duration of protective immunity induced by this system. We show here that mice immunized orally with S. typhimurium vectors expressing a MHC class I-restricted epitope of the lymphocytic choriomeningitis virus (LCMV) nucleoprotein developed specific antiviral CTL responses. CD8+ T cells were found to be necessary for this CTL activity against targets presenting the LCMV epitope. The survival of mice challenged with lethal doses of LCMV 60 or 135 days after vaccination was as complete as the survival of mice challenged 2 weeks after immunization with the same vectors. By demonstrating their ability to induce prolonged protective immunity after oral delivery, S. typhimurium vectors have met an essential requirement in support of their development as vectors for heterologous vaccination.     

Recombinant lymphocytic choriomeningitis virus-based vaccine vector protects type I interferon receptor deficient mice from viral challenge

Reverse genetically engineered recombinant lymphocytic choriomeningitis virus (rLCMV) is a novel vaccine vector platform. Here, we investigate the safety and efficacy of rLCMV in mice lacking a functional type I interferon system with high susceptibility to viral infections. Propagation-deficient rLCMV vector expressing ovalbumin as a model antigen is cleared from type I interferon receptor-deficient mice (Ifnar^-/-) within seven days post vaccination. In Ifnar^-/-, induction of vaccine antigen specific T cells is delayed compared to wild type animals. However, immunization of Ifnar^-/- results in potent memory formation and generates multifunctional cytotoxic CD8⁺ T cells. Most importantly, Ifnar^-/- vaccinated with rLCMV are protected from a challenge with the aggressive LCMV Clone 13. Our data provide evidence for an excellent safety profile with maintained efficacy in immunocompromised animals.