The epidemiology of lymphocytic choriomeningitis virus (LCMV) is the study of the distribution and determinants of the disease caused by this virus in human and animal populations. LCMV is a rodent-borne virus that can cause a variety of clinical manifestations in humans, ranging from asymptomatic to severe neurological disease.
LCMV is mainly transmitted by the standard house mouse (Mus musculus), the natural reservoir and virus-host. The virus can persist in the mouse population without causing symptoms and can be shed in urine, feces, saliva, and blood. Humans can become infected by exposure to these excretions, contact with infected rodents, or their nesting materials.
Infections with LCMV have been documented in Europe, the Americas, Australia, and Japan, but they could appear everywhere that the virus’s rodent hosts are present. Since the disease has historically been underreported, it is frequently challenging to calculate incidence rates or estimates of incidence by geographic area. According to several serologic studies carried out in urban settings, the prevalence of LCMV antibodies in individuals is between 2% and 5%.
LCMV infection can also be transmitted from mother to fetus during pregnancy and cause severe and permanent congenital disabilities such as vision problems, mental retardation, and hydrocephalus. Infections in the first trimester may result in fetal death and pregnancy termination.
The risk of exposure to LCMV is higher for individuals who encounter mice or other rodents, such as pet owners, laboratory workers, veterinarians, pest control workers, and people living in rodent-infested buildings. By avoiding interaction with wild mice, LCMV infection can be prevented.
And their excretions, keeping pet rodents in clean cages away from wild rodents, washing hands after handling rodents or their bedding, and seeking medical attention if symptoms develop after exposure.
The structure of lymphocytic choriomeningitis virus (LCMV) can be summarized in five points as follows:
LCMV is an enveloped, single-stranded RNA virus belonging to the Arenaviridae family.
LCMV has a bisegmented genome consisting of two segments: the large (L) and small (S) segments.
The L segment encodes the viral RNA-dependent RNA polymerase (L protein) and a zinc-binding protein (Z protein). The S segment encodes two viral surface glycoproteins (G1 and G2) and the nucleoprotein (N protein).
The adaptive immune system can produce precise and targeted
and contains the G1 and G2 glycoproteins, which mediate the attachment and entry of the virus into the host cell.
The viral core consists of the ribonucleoprotein complex comprising the L, Z, and N proteins and the genomic RNA. The N protein binds to the RNA segments and forms circular helical structures. The L and Z proteins are associated with the inner surface of the core.
Antigenic Types
There are several strains of LCMV, which differ in their antigenic properties, virulence, and host range. LCMV Armstrong & LCMV Clone 13 are the strains that are most frequently utilised for study. Charles Armstrong first discovered the Armstrong virus strain from the brain in 1934. It triggers a robust cytotoxic T lymphocyte (CTL) response and is cleared rapidly by the host. Clone 13 is a variant of Armstrong derived by serial passage in cell culture. It induces a weak CTL response and persists chronically in the host.
Other strains of LCMV include WE, Traub, Pasteur, and Docile. These strains vary in their ability to infect different rodent species and cause human disease. For example, WE and Traub strains can infect guinea pigs and hamsters, while Pasteur and Docile strains are restricted to mice. WE and Traub strains are more pathogenic for humans than Pasteur and Docile strains.
The antigenic variation among LCMV strains is mainly due to mutations in the glycoprotein (GP) gene, which encodes the surface protein that mediates viral entry and attachment to host cells. The GP gene consists of two segments: GP1 and GP2. GP1 binds to cellular receptors, while GP2 forms the transmembrane domain and the fusion peptide. The GP1 segment is more variable than the GP2 segment among different LCMV strains. The GP1 segment also contains several epitopes recognized by neutralizing antibodies and CTLs. Therefore, mutations in the GP1 segment can affect the antigenicity and virulence of LCMV strains.
Pathogenesis
It is a relatively rare cause of viral infection in humans, but it can lead to significant illness, especially in immunocompromised individuals and pregnant women. Here’s an overview of the pathogenesis of LCMV:
Entry and Initial Infection: LCMV typically enters the human body through contaminated rodent urine, feces, saliva, or bodily fluids. Inhaling aerosolized particles can cause infection in people.
Or directly contacting these fluids. The virus can also be transmitted from mother to fetus during pregnancy, which can have severe consequences for the developing fetus.
Primary Replication: Once LCMV enters the body, it initially infects local cells at the entry site, such as respiratory epithelial cells or cells in the bloodstream. The virus then replicates locally, leading to primary viremia.
Secondary Replication: LCMV can disseminate throughout the body via the bloodstream. It has a particular affinity for lymphoid tissues, where it infects lymphocytes, including B cells and T cells. It can lead to secondary viremia and further spread of the virus.
Immune Response: The host’s immune system recognizes LCMV-infected cells and mounts an immune response. It includes activating cytotoxic T cells (CD8+ T cells) to target and kill infected cells. However, LCMV has developed mechanisms to evade the immune system, allowing it to persist in the host.
Central Nervous System (CNS) Invasion: Sometimes, LCMV can enter the brain and penetrate the blood-brain barrier central nervous system (CNS). Once in the CNS, the virus can infect neurons and glial cells, leading to neurological symptoms. It is a hallmark of severe LCMV infection and can result in aseptic meningitis, encephalitis, or meningoencephalitis.
Host Defenses
The host defenses of LCMV involve innate and adaptive immune systems, which work together to recognize, eliminate, and remember the virus. However, some strains of LCMV can evade or modulate the host defenses, allowing them to persist or cause tissue damage in the host.
The innate immune system is the first line of defense against LCMV infection. It consists of bodily defenses like the skin and mucous membranes and cellular and molecular components, such as natural killer (NK) cells, macrophages, dendritic cells, and interferons (IFNs). The innate immune system recognizes LCMV Via Receptors for pattern recognition (PRRs) of the class TLRs (toll-like receptors) and RIG-I (retinoic acid-inducible gene I), which detect viral nucleic acids or proteins. Upon recognition, the innate immune system produces IFNs, which inhibit viral replication and activate NK cells and macrophages. NK cells and macrophages can kill infected cells by releasing cytotoxic molecules or inducing apoptosis.
The adaptive immune system is the second line of defense against LCMV infection. It consists of B and T cells, which produce antibodies and cytotoxic T lymphocytes (CTLs) against the virus. The adaptive immune system is activated by the presentation of viral antigens by dendritic cells or infected cells to naive B cells and T cells in the lymph nodes or spleen. After activation, B cells develop into secretory plasma cell antibodies that can neutralize the virus or facilitate its clearance by phagocytosis or complement activation. T cells differentiate into helper T cells that provide cytokine signals to B cells and CTLs, or CTLs that kill infected cells by releasing perforin and granzymes or inducing apoptosis. The adaptive immune system also generates memory B and T cells that can quickly respond to future exposure to the same virus.
Clinical manifestations
The symptoms of LCMV infection usually appear 1 to 2 weeks following virus exposure, and they may exhibit a biphasic pattern.
The initial stage is characterized by Flu-like signs of fever, sluggishness, appetite loss, aches and pains in the muscles, headache, nausea, and vomiting characterize the initial stage. Other Less frequent signs and symptoms include testicular pain, chest pain, joint pain, sore throat, and parotid soreness.
After a few days of recovery, the second phase involves signs of meningitis or encephalitis., such as a stiff neck, drowsiness, confusion, sensory disturbances, and motor abnormalities. Some patients may also develop complications such as hydrocephalus, Myelitis, Guillain-Barré syndrome, hearing loss, orchitis, arthritis, parotitis, pneumonitis, pancreatitis, myocarditis, or pericarditis are a few conditions that could be present.
LCMV infection can also be transmitted from mother to fetus during pregnancy and cause severe and permanent congenital disabilities such as vision problems, mental retardation, and hydrocephalus.
Infections in the first trimester may result in fetal death and pregnancy termination.
Most patients with LCMV infection recover fully within 1 to 3 weeks. However, some may have temporary or permanent neurological damage due to the central nervous system infection. Less than 1% of people who contract LCMV die from their infection.
Diagnosis
The diagnosis of lymphocytic choriomeningitis virus (LCMV) is based on detecting the virus or its antibodies in the patient’s blood or cerebrospinal fluid (CSF). Several methods can be used for this purpose, such as:
Viral isolation: This method cultivates the virus from the blood or CSF sample in cell lines or animals. It is a sensitive and specific method but time-consuming, labor-intensive, and requires biosafety level 3 facilities.
Polymerase chain reaction (PCR): This method involves amplifying and detecting the viral RNA from the blood or CSF sample using specific primers and probes. It is a rapid, sensitive, and specific method requiring specialized equipment and trained personnel.
Indirect immunofluorescence (IF): This method involves staining the blood or CSF sample with fluorescent antibodies that bind to the viral antigens. It is an easy and reasonably quick technique but less sensitive and specific than PCR or viral isolation.
Serology: This method involves detecting the presence of antibodies against LCMV in the blood sample using enzyme-linked immunosorbent assay (ELISA) or complement fixation (CF) test. It is a simple and inexpensive method, but it may not be able to distinguish between acute and past infection or between LCMV and other related viruses.
Control
Some of the preventive measures recommended by the CDC are:
Setting up traps and baits to reduce rodent population.
Cleaning up food sources and nesting materials that may attract rodents.
Wearing gloves and a mask when cleaning rodent-infested areas
Inhaling aerosolized particles can cause infection in people.
Keeping pet rodents in a separate room from people with weakened immune systems
Avoid contact with pet rodents that appear sick or have died.
Seeking medical attention if LCMV infection symptoms develop after rodent exposure.
A particular antiviral medication or vaccination is not available for LCMV infection.
»
Home » Pathogen » Lymphocytic choriomeningitis virus
Lymphocytic choriomeningitis virus
Updated :
November 9, 2023
Epidemiology
The epidemiology of lymphocytic choriomeningitis virus (LCMV) is the study of the distribution and determinants of the disease caused by this virus in human and animal populations. LCMV is a rodent-borne virus that can cause a variety of clinical manifestations in humans, ranging from asymptomatic to severe neurological disease.
LCMV is mainly transmitted by the standard house mouse (Mus musculus), the natural reservoir and virus-host. The virus can persist in the mouse population without causing symptoms and can be shed in urine, feces, saliva, and blood. Humans can become infected by exposure to these excretions, contact with infected rodents, or their nesting materials.
Infections with LCMV have been documented in Europe, the Americas, Australia, and Japan, but they could appear everywhere that the virus’s rodent hosts are present. Since the disease has historically been underreported, it is frequently challenging to calculate incidence rates or estimates of incidence by geographic area. According to several serologic studies carried out in urban settings, the prevalence of LCMV antibodies in individuals is between 2% and 5%.
LCMV infection can also be transmitted from mother to fetus during pregnancy and cause severe and permanent congenital disabilities such as vision problems, mental retardation, and hydrocephalus. Infections in the first trimester may result in fetal death and pregnancy termination.
The risk of exposure to LCMV is higher for individuals who encounter mice or other rodents, such as pet owners, laboratory workers, veterinarians, pest control workers, and people living in rodent-infested buildings. By avoiding interaction with wild mice, LCMV infection can be prevented.
And their excretions, keeping pet rodents in clean cages away from wild rodents, washing hands after handling rodents or their bedding, and seeking medical attention if symptoms develop after exposure.
The structure of lymphocytic choriomeningitis virus (LCMV) can be summarized in five points as follows:
LCMV is an enveloped, single-stranded RNA virus belonging to the Arenaviridae family.
LCMV has a bisegmented genome consisting of two segments: the large (L) and small (S) segments.
The L segment encodes the viral RNA-dependent RNA polymerase (L protein) and a zinc-binding protein (Z protein). The S segment encodes two viral surface glycoproteins (G1 and G2) and the nucleoprotein (N protein).
The adaptive immune system can produce precise and targeted
and contains the G1 and G2 glycoproteins, which mediate the attachment and entry of the virus into the host cell.
The viral core consists of the ribonucleoprotein complex comprising the L, Z, and N proteins and the genomic RNA. The N protein binds to the RNA segments and forms circular helical structures. The L and Z proteins are associated with the inner surface of the core.
Antigenic Types
There are several strains of LCMV, which differ in their antigenic properties, virulence, and host range. LCMV Armstrong & LCMV Clone 13 are the strains that are most frequently utilised for study. Charles Armstrong first discovered the Armstrong virus strain from the brain in 1934. It triggers a robust cytotoxic T lymphocyte (CTL) response and is cleared rapidly by the host. Clone 13 is a variant of Armstrong derived by serial passage in cell culture. It induces a weak CTL response and persists chronically in the host.
Other strains of LCMV include WE, Traub, Pasteur, and Docile. These strains vary in their ability to infect different rodent species and cause human disease. For example, WE and Traub strains can infect guinea pigs and hamsters, while Pasteur and Docile strains are restricted to mice. WE and Traub strains are more pathogenic for humans than Pasteur and Docile strains.
The antigenic variation among LCMV strains is mainly due to mutations in the glycoprotein (GP) gene, which encodes the surface protein that mediates viral entry and attachment to host cells. The GP gene consists of two segments: GP1 and GP2. GP1 binds to cellular receptors, while GP2 forms the transmembrane domain and the fusion peptide. The GP1 segment is more variable than the GP2 segment among different LCMV strains. The GP1 segment also contains several epitopes recognized by neutralizing antibodies and CTLs. Therefore, mutations in the GP1 segment can affect the antigenicity and virulence of LCMV strains.
Pathogenesis
It is a relatively rare cause of viral infection in humans, but it can lead to significant illness, especially in immunocompromised individuals and pregnant women. Here’s an overview of the pathogenesis of LCMV:
Entry and Initial Infection: LCMV typically enters the human body through contaminated rodent urine, feces, saliva, or bodily fluids. Inhaling aerosolized particles can cause infection in people.
Or directly contacting these fluids. The virus can also be transmitted from mother to fetus during pregnancy, which can have severe consequences for the developing fetus.
Primary Replication: Once LCMV enters the body, it initially infects local cells at the entry site, such as respiratory epithelial cells or cells in the bloodstream. The virus then replicates locally, leading to primary viremia.
Secondary Replication: LCMV can disseminate throughout the body via the bloodstream. It has a particular affinity for lymphoid tissues, where it infects lymphocytes, including B cells and T cells. It can lead to secondary viremia and further spread of the virus.
Immune Response: The host’s immune system recognizes LCMV-infected cells and mounts an immune response. It includes activating cytotoxic T cells (CD8+ T cells) to target and kill infected cells. However, LCMV has developed mechanisms to evade the immune system, allowing it to persist in the host.
Central Nervous System (CNS) Invasion: Sometimes, LCMV can enter the brain and penetrate the blood-brain barrier central nervous system (CNS). Once in the CNS, the virus can infect neurons and glial cells, leading to neurological symptoms. It is a hallmark of severe LCMV infection and can result in aseptic meningitis, encephalitis, or meningoencephalitis.
Host Defenses
The host defenses of LCMV involve innate and adaptive immune systems, which work together to recognize, eliminate, and remember the virus. However, some strains of LCMV can evade or modulate the host defenses, allowing them to persist or cause tissue damage in the host.
The innate immune system is the first line of defense against LCMV infection. It consists of bodily defenses like the skin and mucous membranes and cellular and molecular components, such as natural killer (NK) cells, macrophages, dendritic cells, and interferons (IFNs). The innate immune system recognizes LCMV Via Receptors for pattern recognition (PRRs) of the class TLRs (toll-like receptors) and RIG-I (retinoic acid-inducible gene I), which detect viral nucleic acids or proteins. Upon recognition, the innate immune system produces IFNs, which inhibit viral replication and activate NK cells and macrophages. NK cells and macrophages can kill infected cells by releasing cytotoxic molecules or inducing apoptosis.
The adaptive immune system is the second line of defense against LCMV infection. It consists of B and T cells, which produce antibodies and cytotoxic T lymphocytes (CTLs) against the virus. The adaptive immune system is activated by the presentation of viral antigens by dendritic cells or infected cells to naive B cells and T cells in the lymph nodes or spleen. After activation, B cells develop into secretory plasma cell antibodies that can neutralize the virus or facilitate its clearance by phagocytosis or complement activation. T cells differentiate into helper T cells that provide cytokine signals to B cells and CTLs, or CTLs that kill infected cells by releasing perforin and granzymes or inducing apoptosis. The adaptive immune system also generates memory B and T cells that can quickly respond to future exposure to the same virus.
Clinical manifestations
The symptoms of LCMV infection usually appear 1 to 2 weeks following virus exposure, and they may exhibit a biphasic pattern.
The initial stage is characterized by Flu-like signs of fever, sluggishness, appetite loss, aches and pains in the muscles, headache, nausea, and vomiting characterize the initial stage. Other Less frequent signs and symptoms include testicular pain, chest pain, joint pain, sore throat, and parotid soreness.
After a few days of recovery, the second phase involves signs of meningitis or encephalitis., such as a stiff neck, drowsiness, confusion, sensory disturbances, and motor abnormalities. Some patients may also develop complications such as hydrocephalus, Myelitis, Guillain-Barré syndrome, hearing loss, orchitis, arthritis, parotitis, pneumonitis, pancreatitis, myocarditis, or pericarditis are a few conditions that could be present.
LCMV infection can also be transmitted from mother to fetus during pregnancy and cause severe and permanent congenital disabilities such as vision problems, mental retardation, and hydrocephalus.
Infections in the first trimester may result in fetal death and pregnancy termination.
Most patients with LCMV infection recover fully within 1 to 3 weeks. However, some may have temporary or permanent neurological damage due to the central nervous system infection. Less than 1% of people who contract LCMV die from their infection.
Diagnosis
The diagnosis of lymphocytic choriomeningitis virus (LCMV) is based on detecting the virus or its antibodies in the patient’s blood or cerebrospinal fluid (CSF). Several methods can be used for this purpose, such as:
Viral isolation: This method cultivates the virus from the blood or CSF sample in cell lines or animals. It is a sensitive and specific method but time-consuming, labor-intensive, and requires biosafety level 3 facilities.
Polymerase chain reaction (PCR): This method involves amplifying and detecting the viral RNA from the blood or CSF sample using specific primers and probes. It is a rapid, sensitive, and specific method requiring specialized equipment and trained personnel.
Indirect immunofluorescence (IF): This method involves staining the blood or CSF sample with fluorescent antibodies that bind to the viral antigens. It is an easy and reasonably quick technique but less sensitive and specific than PCR or viral isolation.
Serology: This method involves detecting the presence of antibodies against LCMV in the blood sample using enzyme-linked immunosorbent assay (ELISA) or complement fixation (CF) test. It is a simple and inexpensive method, but it may not be able to distinguish between acute and past infection or between LCMV and other related viruses.
Control
Some of the preventive measures recommended by the CDC are:
Setting up traps and baits to reduce rodent population.
Cleaning up food sources and nesting materials that may attract rodents.
Wearing gloves and a mask when cleaning rodent-infested areas
Inhaling aerosolized particles can cause infection in people.
Keeping pet rodents in a separate room from people with weakened immune systems
Avoid contact with pet rodents that appear sick or have died.
Seeking medical attention if LCMV infection symptoms develop after rodent exposure.
A particular antiviral medication or vaccination is not available for LCMV infection.
The epidemiology of lymphocytic choriomeningitis virus (LCMV) is the study of the distribution and determinants of the disease caused by this virus in human and animal populations. LCMV is a rodent-borne virus that can cause a variety of clinical manifestations in humans, ranging from asymptomatic to severe neurological disease.
LCMV is mainly transmitted by the standard house mouse (Mus musculus), the natural reservoir and virus-host. The virus can persist in the mouse population without causing symptoms and can be shed in urine, feces, saliva, and blood. Humans can become infected by exposure to these excretions, contact with infected rodents, or their nesting materials.
Infections with LCMV have been documented in Europe, the Americas, Australia, and Japan, but they could appear everywhere that the virus’s rodent hosts are present. Since the disease has historically been underreported, it is frequently challenging to calculate incidence rates or estimates of incidence by geographic area. According to several serologic studies carried out in urban settings, the prevalence of LCMV antibodies in individuals is between 2% and 5%.
LCMV infection can also be transmitted from mother to fetus during pregnancy and cause severe and permanent congenital disabilities such as vision problems, mental retardation, and hydrocephalus. Infections in the first trimester may result in fetal death and pregnancy termination.
The risk of exposure to LCMV is higher for individuals who encounter mice or other rodents, such as pet owners, laboratory workers, veterinarians, pest control workers, and people living in rodent-infested buildings. By avoiding interaction with wild mice, LCMV infection can be prevented.
And their excretions, keeping pet rodents in clean cages away from wild rodents, washing hands after handling rodents or their bedding, and seeking medical attention if symptoms develop after exposure.
The structure of lymphocytic choriomeningitis virus (LCMV) can be summarized in five points as follows:
LCMV is an enveloped, single-stranded RNA virus belonging to the Arenaviridae family.
LCMV has a bisegmented genome consisting of two segments: the large (L) and small (S) segments.
The L segment encodes the viral RNA-dependent RNA polymerase (L protein) and a zinc-binding protein (Z protein). The S segment encodes two viral surface glycoproteins (G1 and G2) and the nucleoprotein (N protein).
The adaptive immune system can produce precise and targeted
and contains the G1 and G2 glycoproteins, which mediate the attachment and entry of the virus into the host cell.
The viral core consists of the ribonucleoprotein complex comprising the L, Z, and N proteins and the genomic RNA. The N protein binds to the RNA segments and forms circular helical structures. The L and Z proteins are associated with the inner surface of the core.
Antigenic Types
There are several strains of LCMV, which differ in their antigenic properties, virulence, and host range. LCMV Armstrong & LCMV Clone 13 are the strains that are most frequently utilised for study. Charles Armstrong first discovered the Armstrong virus strain from the brain in 1934. It triggers a robust cytotoxic T lymphocyte (CTL) response and is cleared rapidly by the host. Clone 13 is a variant of Armstrong derived by serial passage in cell culture. It induces a weak CTL response and persists chronically in the host.
Other strains of LCMV include WE, Traub, Pasteur, and Docile. These strains vary in their ability to infect different rodent species and cause human disease. For example, WE and Traub strains can infect guinea pigs and hamsters, while Pasteur and Docile strains are restricted to mice. WE and Traub strains are more pathogenic for humans than Pasteur and Docile strains.
The antigenic variation among LCMV strains is mainly due to mutations in the glycoprotein (GP) gene, which encodes the surface protein that mediates viral entry and attachment to host cells. The GP gene consists of two segments: GP1 and GP2. GP1 binds to cellular receptors, while GP2 forms the transmembrane domain and the fusion peptide. The GP1 segment is more variable than the GP2 segment among different LCMV strains. The GP1 segment also contains several epitopes recognized by neutralizing antibodies and CTLs. Therefore, mutations in the GP1 segment can affect the antigenicity and virulence of LCMV strains.
Pathogenesis
It is a relatively rare cause of viral infection in humans, but it can lead to significant illness, especially in immunocompromised individuals and pregnant women. Here’s an overview of the pathogenesis of LCMV:
Entry and Initial Infection: LCMV typically enters the human body through contaminated rodent urine, feces, saliva, or bodily fluids. Inhaling aerosolized particles can cause infection in people.
Or directly contacting these fluids. The virus can also be transmitted from mother to fetus during pregnancy, which can have severe consequences for the developing fetus.
Primary Replication: Once LCMV enters the body, it initially infects local cells at the entry site, such as respiratory epithelial cells or cells in the bloodstream. The virus then replicates locally, leading to primary viremia.
Secondary Replication: LCMV can disseminate throughout the body via the bloodstream. It has a particular affinity for lymphoid tissues, where it infects lymphocytes, including B cells and T cells. It can lead to secondary viremia and further spread of the virus.
Immune Response: The host’s immune system recognizes LCMV-infected cells and mounts an immune response. It includes activating cytotoxic T cells (CD8+ T cells) to target and kill infected cells. However, LCMV has developed mechanisms to evade the immune system, allowing it to persist in the host.
Central Nervous System (CNS) Invasion: Sometimes, LCMV can enter the brain and penetrate the blood-brain barrier central nervous system (CNS). Once in the CNS, the virus can infect neurons and glial cells, leading to neurological symptoms. It is a hallmark of severe LCMV infection and can result in aseptic meningitis, encephalitis, or meningoencephalitis.
Host Defenses
The host defenses of LCMV involve innate and adaptive immune systems, which work together to recognize, eliminate, and remember the virus. However, some strains of LCMV can evade or modulate the host defenses, allowing them to persist or cause tissue damage in the host.
The innate immune system is the first line of defense against LCMV infection. It consists of bodily defenses like the skin and mucous membranes and cellular and molecular components, such as natural killer (NK) cells, macrophages, dendritic cells, and interferons (IFNs). The innate immune system recognizes LCMV Via Receptors for pattern recognition (PRRs) of the class TLRs (toll-like receptors) and RIG-I (retinoic acid-inducible gene I), which detect viral nucleic acids or proteins. Upon recognition, the innate immune system produces IFNs, which inhibit viral replication and activate NK cells and macrophages. NK cells and macrophages can kill infected cells by releasing cytotoxic molecules or inducing apoptosis.
The adaptive immune system is the second line of defense against LCMV infection. It consists of B and T cells, which produce antibodies and cytotoxic T lymphocytes (CTLs) against the virus. The adaptive immune system is activated by the presentation of viral antigens by dendritic cells or infected cells to naive B cells and T cells in the lymph nodes or spleen. After activation, B cells develop into secretory plasma cell antibodies that can neutralize the virus or facilitate its clearance by phagocytosis or complement activation. T cells differentiate into helper T cells that provide cytokine signals to B cells and CTLs, or CTLs that kill infected cells by releasing perforin and granzymes or inducing apoptosis. The adaptive immune system also generates memory B and T cells that can quickly respond to future exposure to the same virus.
Clinical manifestations
The symptoms of LCMV infection usually appear 1 to 2 weeks following virus exposure, and they may exhibit a biphasic pattern.
The initial stage is characterized by Flu-like signs of fever, sluggishness, appetite loss, aches and pains in the muscles, headache, nausea, and vomiting characterize the initial stage. Other Less frequent signs and symptoms include testicular pain, chest pain, joint pain, sore throat, and parotid soreness.
After a few days of recovery, the second phase involves signs of meningitis or encephalitis., such as a stiff neck, drowsiness, confusion, sensory disturbances, and motor abnormalities. Some patients may also develop complications such as hydrocephalus, Myelitis, Guillain-Barré syndrome, hearing loss, orchitis, arthritis, parotitis, pneumonitis, pancreatitis, myocarditis, or pericarditis are a few conditions that could be present.
LCMV infection can also be transmitted from mother to fetus during pregnancy and cause severe and permanent congenital disabilities such as vision problems, mental retardation, and hydrocephalus.
Infections in the first trimester may result in fetal death and pregnancy termination.
Most patients with LCMV infection recover fully within 1 to 3 weeks. However, some may have temporary or permanent neurological damage due to the central nervous system infection. Less than 1% of people who contract LCMV die from their infection.
Diagnosis
The diagnosis of lymphocytic choriomeningitis virus (LCMV) is based on detecting the virus or its antibodies in the patient’s blood or cerebrospinal fluid (CSF). Several methods can be used for this purpose, such as:
Viral isolation: This method cultivates the virus from the blood or CSF sample in cell lines or animals. It is a sensitive and specific method but time-consuming, labor-intensive, and requires biosafety level 3 facilities.
Polymerase chain reaction (PCR): This method involves amplifying and detecting the viral RNA from the blood or CSF sample using specific primers and probes. It is a rapid, sensitive, and specific method requiring specialized equipment and trained personnel.
Indirect immunofluorescence (IF): This method involves staining the blood or CSF sample with fluorescent antibodies that bind to the viral antigens. It is an easy and reasonably quick technique but less sensitive and specific than PCR or viral isolation.
Serology: This method involves detecting the presence of antibodies against LCMV in the blood sample using enzyme-linked immunosorbent assay (ELISA) or complement fixation (CF) test. It is a simple and inexpensive method, but it may not be able to distinguish between acute and past infection or between LCMV and other related viruses.
Control
Some of the preventive measures recommended by the CDC are:
Setting up traps and baits to reduce rodent population.
Cleaning up food sources and nesting materials that may attract rodents.
Wearing gloves and a mask when cleaning rodent-infested areas
Inhaling aerosolized particles can cause infection in people.
Keeping pet rodents in a separate room from people with weakened immune systems
Avoid contact with pet rodents that appear sick or have died.
Seeking medical attention if LCMV infection symptoms develop after rodent exposure.
A particular antiviral medication or vaccination is not available for LCMV infection.
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