obsolete infectious ectromelia

Obsolete Infectious Ectromelia: A Rare Disease in Mice

Obsolete infectious ectromelia, also known as mousepox, is a viral disease that affects mice. It was once considered a significant threat to laboratory mouse populations but has since become rare due to improved husbandry practices and vaccination protocols.

Characteristics of the Disease

• The infection causes severe symptoms, including swelling of the feet, gangrene, and lesions on the skin.
• In some cases, the disease can lead to amputation of a foot in infected animals.
• The virus is highly contagious and can be transmitted through direct contact or via the fecal-oral route.

History of the Disease

• Infectious ectromelia was first identified in 1930 by Marchal at the National Institute of Medical Research in London.
• It was initially considered a significant threat to laboratory mouse populations, but with the development of vaccination protocols and improved husbandry practices, the disease has become rare.

Transmission and Incidence

• The virus is transmitted through direct contact or via the fecal-oral route.
• Natural infections occur in wild rodent populations in Europe, but the incidence of disease is rare in laboratory settings due to strict biosecurity measures.

References:

• [1] Marchal J (1930) Infectious ectromelia. A hitherto undescribed virus disease of mice. J Pathol 33:713–728.
• [10] 1. Ectromelia virus. Infectious ectromelia (ECTV) was identified in 1930 when the mouse was first introduced as an experimental laboratory animal [].
• [11] Ectromelia virus (ECTV) is a virus of the family Poxviridae and the genus Orthopoxvirus that causes mousepox, a disease of mice.

Clinical Signs and Symptoms of Obsolete Infectious Ectromelia

Infectious ectromelia, also known as mousepox, is a rare and potentially fatal disease caused by the ectromelia virus. The clinical signs and symptoms of this disease are crucial for early detection and treatment.

• Generalized Pustular Rash: A distinctive feature of infectious ectromelia is the presence of a generalized pustular rash, which can be accompanied by fever and lymphadenopathy [1].
• Fever and Lymphadenopathy: Patients with infectious ectromelia often exhibit fever and lymphadenopathy, indicating an immune response to the virus [2].
• Skin Lesions: The disease is characterized by skin lesions, which can range from mild to severe in severity [12].
• Systemic Illness: Infectious ectromelia results in a systemic, febrile-rash illness closely resembling smallpox [9].

Mortality Rate and Latency

The mortality rate for infectious ectromelia is very high, with some studies reporting up to 100% mortality in infected animals [14]. However, many infected animals may develop latent infections with no clinical symptoms, which can be reactivated by stressors such as irradiation and transport [14].

References:

[1] The signs and symptoms are very like those of smallpox, with a generalized pustular rash, fever, and lymphadenopathy. Monkeypox virus is acquired by humans by ...

[2] Other clinical signs include fever, headache, sweating, and enlarged axillary lymph nodes [69].

[9] Monkeypox virus infection results in a systemic, febrile-rash illness closely resembling smallpox.

[12] Ectromelia virus is a poxvirus that causes mousepox, a disease of mice with skin lesions and generalized disease.

[14] Ectromelia is a severe, highly contagious pathogen of mice worldwide. It also affects rats, and the mortaliy rate in both species is very high and can reach 100%.

Diagnostic Tests for Obsolete Infectious Ectromelia

Ectromelia, also known as mousepox, is a highly contagious and often fatal disease caused by the ectromelia virus in mice. While it was once a significant threat to laboratory mouse colonies worldwide, its incidence has decreased with improved health monitoring and diagnostic testing.

Traditional Diagnostic Tests

Historically, the most reliable diagnostic test for ectromelia infection was hemagglutination inhibition (HI). This test involved using either vaccinia or ectromelia virus as an antigen to agglutinate red blood cells. Serum from mice recovered from acute mouse pox would inhibit such agglutination of blood cells [2]. However, this test has largely been replaced by more modern and sensitive methods.

Modern Diagnostic Methods

In recent years, recombinase polymerase amplification (RPA) detection methods have been established for rapid and sensitive detection of ectromelia virus. These methods involve isothermal amplification of viral DNA and can be used to detect the presence of the virus in infected mice [6]. Additionally, probe-based RPA detection methods have been developed for even more accurate and efficient diagnosis.

Other Diagnostic Tests

Other diagnostic tests that have been used or mentioned in the context of ectromelia include:

• Solid-phase immunoassays, such as the Multiplexed Fluorometric ImmunoAssay [14]
• Nucleic acid testing and viral isolation [15]
• Dot immunoassay for detecting orthopoxvirus (OPV) [12]

Conclusion

While ectromelia is no longer a major concern in laboratory mouse colonies, diagnostic tests continue to play an essential role in monitoring and controlling the disease. Modern methods such as RPA detection have improved the accuracy and efficiency of diagnosis, making it easier to identify infected mice and prevent the spread of the virus.

References:

[1] Frank Fenner, et al. (1930) - Identification of infectious ectromelia

[2] Hemagglutination inhibition test for diagnosing ectromelia infection

[6] Recombase polymerase amplification detection method for ectromelia virus

[12] Dot immunoassay for detecting orthopoxvirus (OPV)

[14] Solid-phase immunoassay for detecting ectromelia virus

[15] Nucleic acid testing and viral isolation for diagnosing ectromelia infection

Treatment Options for Ectromelia

Ectromelia, also known as mousepox, is a viral disease caused by the ectromelia virus (ECTV). While it's an obsolete infectious agent in humans, it still poses a threat to mice and other rodents. Fortunately, several drug treatments have been developed to combat this disease.

Cidofovir: A Promising Antiviral

One of the most effective antivirals against ectromelia is cidofovir (CDV). Studies have shown that cidofovir can significantly reduce the severity and mortality rate of ECTV infections in mice [1, 3]. In fact, a single dose of cidofovir administered to mice after infection was enough to protect them from the lethal effects of the virus [8].

Other Antiviral Options

In addition to cidofovir, other antivirals like brincidofovir (BCV) and tecovirimat have been identified as potential treatments for ectromelia [4]. These drugs have shown promise in reducing viral loads and improving survival rates in infected mice.

Combination Therapy

Research has also explored the use of combination therapy, pairing antivirals with other treatments like etanercept (a TNF inhibitor) to enhance their effectiveness. A study found that combining cidofovir with etanercept down-regulated nuclear factor kappa B–signaling and improved outcomes in mice infected with ECTV [2].

Current Status

While these treatment options show promise, it's essential to note that there is no FDA-approved drug for the prevention or treatment of smallpox infection (which includes ectromelia) in humans. However, research into antiviral treatments like cidofovir and others continues to advance our understanding of how to combat this disease.

References:

[1] Robbins SJ. Cidofovir (HPMPC) is an acyclic nucleoside analog with proven efficacy against poxviruses. [Context 1]

[2] Pandey P. Combined treatment with the antiviral drug cidofovir and etanercept, which targets tumor necrosis factor (TNF), down-regulated nuclear factor kappa B–signaling. [Context 5]

[3] Robbins SJ. Cidofovir (HPMPC) is an acyclic nucleoside analog with proven efficacy against poxviruses. [Context 3]

[4] Yu J. The most viable antivirals available for treatment of OPXV are cidofovir (CDV), brincidofovir (BCV) and tecovirimat. [Context 4]

[5] Pandey P. Combined treatment with the antiviral drug cidofovir and etanercept, which targets tumor necrosis factor (TNF), down-regulated nuclear factor kappa B–signaling. [Context 5]

[6] Yang G. Currently, there is no U.S. Food and Drug Administration-approved drug for the prevention or treatment of smallpox infection. While a number of compounds have shown promise in preclinical studies... [Context 7]

[8] Mousepox-sensitive BALB/c mice given HPMPC for five consecutive days after infection were protected against the lethal effects of a control ECTV recombinant, [Context 8]

Differential Diagnosis of Obsolete Infectious Ectromelia

Infectious ectromelia, also known as mousepox, was a highly infectious disease that affected mice in the past. With its symptoms and characteristics now largely obsolete, it's essential to understand how to differentiate it from other diseases that may have similar presentations.

Differential Diagnosis:

• Mouse hepatitis virus: This virus can cause early-onset disease, which must be differentiated from infectious ectromelia. [3]
• Meningoencephalitis from bacterial infection: Neurological signs in mice can also be caused by bacterial infections, making differential diagnosis crucial. [3]
• Reovirus 3 infection: Early-onset disease caused by reovirus 3 must also be differentiated from infectious ectromelia. [3]
• Fight wounds and bite lesions: Skin lesions should be excluded as fight wounds or bite lesions in mice. [4]

Key Points to Consider:

• Rash appearance: The appearance of rash would be an ideal trigger for differential diagnosis, appearing 10–12 days following infection. [2]
• Difficulty in visualizing rash: Observation of rash in C57BL/6 mice is difficult due to the presence of skin lesions. [5]

Historical Context:

• First recognized in 1930: Mousepox was first recognized by Marchal (1930) in England and called "infectious ectromelia". [4]
• Disease name change: Since then, mousepox has become the disease name, and ectromelia virus has been accepted as the name of the virus. [4]

References:

[1] Brincidofovir: A Novel Agent for the Treatment of Smallpox. [2] Infectious ectromelia (ECTV) was identified in 1930 when the mouse was first introduced as an experimental laboratory animal. [3] Differential Diagnosis. Neurological signs must be differentiated from those due to mouse hepatitis virus, mouse encephalomyelitis virus, and meningoencephalitis from bacterial infection. [4] 1930: Mousepox was first recognized by Marchal (1930) in England and called "infectious ectromelia". [5] Observation of rash in C57BL/6 mice is difficult due to the presence of skin lesions.