http://www.promedmail.org/
Published Date: 2012-08-16 16:42:10
Subject: PRO/AH/EDR> Human lymphocytic choriomeningitis virus - USA: (IN) rodent house
Archive Number: 20120816.1247976
HUMAN LYMPHOCYTIC CHORIOMENINGITIS VIRUS - USA: (INDIANA) RODENT HOUSE
**********************************************************************
A ProMED-mail post
http://www.promedmail.org
ProMED-mail is a program of the
International Society for Infectious Diseases
http://www.isid.org
Date: Fri 17 Aug 2012
Source: MMWR Weekly 61(32);622-623, Notes from the Field [edited]
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6132a5.htm?s_cid=mm6132a5_e
In late April 2012, an infectious disease physician contacted the Centers for Disease Control and Prevention (CDC) regarding a patient with aseptic meningitis who worked at a rodent breeding facility in Indiana. Lymphocytic choriomeningitis virus (LCMV) infection was suspected, and LCMV-specific antibody was detected in blood and cerebrospinal fluid from the patient, confirming the diagnosis. LCMV is an arenavirus carried by the common house mouse. Persons become infected through close contact with infected rodents, through infected organ transplantation, or from mother to fetus. In immunocompetent adults, symptoms can range from mild febrile illness to meningeal symptoms (for example, headache, stiff neck, or sensitivity to light). Congenitally infected infants can have a range of severe birth defects including hydrocephalus, chorioretinitis, blindness, and mental retardation (1). Infections in organ recipients, who are immunosuppressed, can have a case fatality rate approaching 90 per cent (2).
CDC notified the Indiana State Department of Health of a potential outbreak of LCMV infection at the rodent breeding facility and subsequently notified county health officials and the Indiana Board of Animal Health. A serosurvey was performed; 52 current and former employees of the facility consented to serum testing. Of the 52 tested, 13 (25 per cent) demonstrated recent LCMV infection as evidenced by the presence of immunoglobulin M (IgM) and IgG by enzyme-linked immunosorbent assay (ELISA). Nine employees who showed laboratory evidence of recent exposure reported experiencing a clinical illness consistent with LCMV; symptoms ranged from severe influenza-like illness to meningeal symptoms that required hospitalization. Of the persons experiencing illness, 89 per cent were male; ages ranged from 20 to 48 years. No employees, including those not tested, were known to be pregnant at the time of the serosurvey. All employees who experienced clinical illness have since recovered. Three additional employees had evidence of a previous LCMV infection, with detectable anti-LCMV IgG and no IgM.
The rodent facility bred and raised mice and rats for sale as live and frozen feeder animals for reptiles or birds of prey. The facility housed about 155 000 adult mice and 14 000 adult rats. A representative sample of healthy-appearing adult rodents was tested for evidence of LCMV infection by ELISA and polymerase chain reaction. Of 1421 mice tested, 296 (20.8 per cent) had detectable anti-LCMV IgG, and 10 (0.7 per cent) had detectable LCMV RNA. Of 399 rats tested, none were positive by ELISA or polymerase chain reaction. All living mice at the facility were euthanized. All rodents remaining in cold storage at the time of diagnosis also were disposed of in accordance with local environmental regulations. The buildings and equipment housing the mice were cleaned and disinfected. Used litter and contaminated feed were disposed of in accordance with local environmental regulations. Live mice distributed from the facility before the LCMV diagnosis currently are being followed to the point of purchase through an ongoing investigation.
Any persons with direct or indirect contact with these animals should be made aware of the public health risk and should seek medical evaluation if they have had any recent illness. Pregnant women or immunocompromised persons should be cautioned to avoid contact with rodents in general. Wild mice in the United States have a prevalence of LCMV estimated at 3.9-13.4 per cent (3). Any additional rodent populations that have come into direct contact with potentially infected mice should be depopulated.
Employers of rodent breeding facilities of all kinds should make their employees aware that working with rodents can expose them to LCMV and should educate workers regarding risks for exposure, including potential health effects. Employers also should work with their local health departments to develop guidance material on disease prevention and provide the recommended personal protective equipment for employees. Routine serologic testing of rodents can be used to detect and control LCMV infections. Evidence of LCMV infection in rodents should be dealt with promptly to prevent human illness from occurring. Purchasers of frozen rodents used to feed another pet should be reminded to always wear plastic gloves when handling the rodents and to wash their hands afterward.
References
1. Bonthius DJ. Lymphocytic choriomeningitis virus: a prenatal and postnatal threat. Adv Pediatr 2009; 56: 75-86.
2. MacNeil A, Stroher U, Farnon E, et al. Solid organ transplant-associated lymphocytic choriomeningitis, United States, 2011. Emerg Infect Dis 2012; 18: 1256-62.
3. Childs JE, Glass GE, Korch GW, Ksiazek TG, Leduc JW. Lymphocytic choriomeningitis virus infection and house mouse (_Mus musculus_) distribution in urban Baltimore. Am J Trop Med Hyg 1992; 47: 27-34.
--
communicated by:
ProMED-mail<promed@promedmail.org>
[Lymphocytic choriomeningitis, or LCM, is a rodentborne viral infectious disease that presents as aseptic meningitis (inflammation of the membrane, or meninges, that surrounds the brain and spinal cord), encephalitis (inflammation of the brain), or meningoencephalitis (inflammation of both the brain and meninges). Its causative agent is the lymphocytic choriomeningitis virus (LCMV), a member of the family _Arenaviridae_ that was initially isolated in 1933. Although LCMV is most commonly recognized as causing neurological disease, as its name implies, infection without symptoms or mild febrile illnesses are common clinical manifestations. In addition, pregnancy-related infection has been associated with congenital hydrocephalus, chorioretinitis, and mental retardation.
The primary host is the common house mouse, _Mus musculus_. Infection in house mouse populations may vary by geographic location; about 5 per cent of mice throughout the United States carry LCMV. The virus is found in the saliva, urine, and feces of infected mice. Infected mice carry LCMV and shed it for the duration of their lives without showing any sign of illness. Other types of rodents, such as hamsters, are not the natural reservoirs but can become infected with LCMV from wild mice at the breeder, in the pet store or home environment. Humans are more likely to contract LCMV from house mice, but infections from pet rodents have also been reported. Individuals become infected with LCMV after exposure to fresh urine, droppings, saliva, or nesting materials. Transmission can also occur when these materials are directly introduced into broken skin, the nose, the eyes, or the mouth, or presumably, via the bite of an infected rodent. Person-to-person transmission has not been reported, with the exception of vertical transmission from infected mother to fetus. Recent investigations indicate that organ transplantation may also be a means of transmission.
LCM and milder LCMV infections have been reported in Europe, the Americas, Australia, and Japan, and may occur wherever infected rodent hosts of the virus are found. However, the disease has historically been underreported, often making it difficult to determine incidence rates or estimates of prevalence by geographic region. Several serologic studies conducted in urban areas have shown that the prevalence of LCMV infection among humans ranges from 2 to 5 per cent.
Further information on symptoms, complications, treatment and risk factors can be fond at the CDC website at http://www.cdc.gov/ncidod/dvrd/spb/mnpages/dispages/lcmv/qa.htm. - Mod.CP
A HealthMap/ProMED-mail map can be accessed at: http://healthmap.org/r/1DmR.]
Published Date: 2012-08-16 16:42:10
Subject: PRO/AH/EDR> Human lymphocytic choriomeningitis virus - USA: (IN) rodent house
Archive Number: 20120816.1247976
HUMAN LYMPHOCYTIC CHORIOMENINGITIS VIRUS - USA: (INDIANA) RODENT HOUSE
**********************************************************************
A ProMED-mail post
http://www.promedmail.org
ProMED-mail is a program of the
International Society for Infectious Diseases
http://www.isid.org
Date: Fri 17 Aug 2012
Source: MMWR Weekly 61(32);622-623, Notes from the Field [edited]
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6132a5.htm?s_cid=mm6132a5_e
In late April 2012, an infectious disease physician contacted the Centers for Disease Control and Prevention (CDC) regarding a patient with aseptic meningitis who worked at a rodent breeding facility in Indiana. Lymphocytic choriomeningitis virus (LCMV) infection was suspected, and LCMV-specific antibody was detected in blood and cerebrospinal fluid from the patient, confirming the diagnosis. LCMV is an arenavirus carried by the common house mouse. Persons become infected through close contact with infected rodents, through infected organ transplantation, or from mother to fetus. In immunocompetent adults, symptoms can range from mild febrile illness to meningeal symptoms (for example, headache, stiff neck, or sensitivity to light). Congenitally infected infants can have a range of severe birth defects including hydrocephalus, chorioretinitis, blindness, and mental retardation (1). Infections in organ recipients, who are immunosuppressed, can have a case fatality rate approaching 90 per cent (2).
CDC notified the Indiana State Department of Health of a potential outbreak of LCMV infection at the rodent breeding facility and subsequently notified county health officials and the Indiana Board of Animal Health. A serosurvey was performed; 52 current and former employees of the facility consented to serum testing. Of the 52 tested, 13 (25 per cent) demonstrated recent LCMV infection as evidenced by the presence of immunoglobulin M (IgM) and IgG by enzyme-linked immunosorbent assay (ELISA). Nine employees who showed laboratory evidence of recent exposure reported experiencing a clinical illness consistent with LCMV; symptoms ranged from severe influenza-like illness to meningeal symptoms that required hospitalization. Of the persons experiencing illness, 89 per cent were male; ages ranged from 20 to 48 years. No employees, including those not tested, were known to be pregnant at the time of the serosurvey. All employees who experienced clinical illness have since recovered. Three additional employees had evidence of a previous LCMV infection, with detectable anti-LCMV IgG and no IgM.
The rodent facility bred and raised mice and rats for sale as live and frozen feeder animals for reptiles or birds of prey. The facility housed about 155 000 adult mice and 14 000 adult rats. A representative sample of healthy-appearing adult rodents was tested for evidence of LCMV infection by ELISA and polymerase chain reaction. Of 1421 mice tested, 296 (20.8 per cent) had detectable anti-LCMV IgG, and 10 (0.7 per cent) had detectable LCMV RNA. Of 399 rats tested, none were positive by ELISA or polymerase chain reaction. All living mice at the facility were euthanized. All rodents remaining in cold storage at the time of diagnosis also were disposed of in accordance with local environmental regulations. The buildings and equipment housing the mice were cleaned and disinfected. Used litter and contaminated feed were disposed of in accordance with local environmental regulations. Live mice distributed from the facility before the LCMV diagnosis currently are being followed to the point of purchase through an ongoing investigation.
Any persons with direct or indirect contact with these animals should be made aware of the public health risk and should seek medical evaluation if they have had any recent illness. Pregnant women or immunocompromised persons should be cautioned to avoid contact with rodents in general. Wild mice in the United States have a prevalence of LCMV estimated at 3.9-13.4 per cent (3). Any additional rodent populations that have come into direct contact with potentially infected mice should be depopulated.
Employers of rodent breeding facilities of all kinds should make their employees aware that working with rodents can expose them to LCMV and should educate workers regarding risks for exposure, including potential health effects. Employers also should work with their local health departments to develop guidance material on disease prevention and provide the recommended personal protective equipment for employees. Routine serologic testing of rodents can be used to detect and control LCMV infections. Evidence of LCMV infection in rodents should be dealt with promptly to prevent human illness from occurring. Purchasers of frozen rodents used to feed another pet should be reminded to always wear plastic gloves when handling the rodents and to wash their hands afterward.
References
1. Bonthius DJ. Lymphocytic choriomeningitis virus: a prenatal and postnatal threat. Adv Pediatr 2009; 56: 75-86.
2. MacNeil A, Stroher U, Farnon E, et al. Solid organ transplant-associated lymphocytic choriomeningitis, United States, 2011. Emerg Infect Dis 2012; 18: 1256-62.
3. Childs JE, Glass GE, Korch GW, Ksiazek TG, Leduc JW. Lymphocytic choriomeningitis virus infection and house mouse (_Mus musculus_) distribution in urban Baltimore. Am J Trop Med Hyg 1992; 47: 27-34.
--
communicated by:
ProMED-mail<promed@promedmail.org>
[Lymphocytic choriomeningitis, or LCM, is a rodentborne viral infectious disease that presents as aseptic meningitis (inflammation of the membrane, or meninges, that surrounds the brain and spinal cord), encephalitis (inflammation of the brain), or meningoencephalitis (inflammation of both the brain and meninges). Its causative agent is the lymphocytic choriomeningitis virus (LCMV), a member of the family _Arenaviridae_ that was initially isolated in 1933. Although LCMV is most commonly recognized as causing neurological disease, as its name implies, infection without symptoms or mild febrile illnesses are common clinical manifestations. In addition, pregnancy-related infection has been associated with congenital hydrocephalus, chorioretinitis, and mental retardation.
The primary host is the common house mouse, _Mus musculus_. Infection in house mouse populations may vary by geographic location; about 5 per cent of mice throughout the United States carry LCMV. The virus is found in the saliva, urine, and feces of infected mice. Infected mice carry LCMV and shed it for the duration of their lives without showing any sign of illness. Other types of rodents, such as hamsters, are not the natural reservoirs but can become infected with LCMV from wild mice at the breeder, in the pet store or home environment. Humans are more likely to contract LCMV from house mice, but infections from pet rodents have also been reported. Individuals become infected with LCMV after exposure to fresh urine, droppings, saliva, or nesting materials. Transmission can also occur when these materials are directly introduced into broken skin, the nose, the eyes, or the mouth, or presumably, via the bite of an infected rodent. Person-to-person transmission has not been reported, with the exception of vertical transmission from infected mother to fetus. Recent investigations indicate that organ transplantation may also be a means of transmission.
LCM and milder LCMV infections have been reported in Europe, the Americas, Australia, and Japan, and may occur wherever infected rodent hosts of the virus are found. However, the disease has historically been underreported, often making it difficult to determine incidence rates or estimates of prevalence by geographic region. Several serologic studies conducted in urban areas have shown that the prevalence of LCMV infection among humans ranges from 2 to 5 per cent.
Further information on symptoms, complications, treatment and risk factors can be fond at the CDC website at http://www.cdc.gov/ncidod/dvrd/spb/mnpages/dispages/lcmv/qa.htm. - Mod.CP
A HealthMap/ProMED-mail map can be accessed at: http://healthmap.org/r/1DmR.]