Cowpox - Clinicals, Diagnosis, and Management

Infectious diseases

Clinicals - History

Fact Explanation
Skin rash The cowpox or catpox virus is a zoonotic member of the family orthopoxviride. It is transferable from animal to human. It is acquired by direct contact with an infected animal (cat in most of cases) to a human during a scratch or bite . Cowpox infection is very rare nowadays. Most cases have been reported in Great Britain and other European countries. In cowpox disease, small number of skin lesions appears on the hands and face.
Initially the site of infection appears as an inflamed flat red lesion (macule). Then, the inflamed lesion becomes raised (papular) and develops into a blister-like sore (vesicle).
Skin rash
The cowpox or catpox virus is a zoonotic member of the family orthopoxviride. It is transferable from animal to human. It is acquired by direct contact with an infected animal (cat in most of cases) to a human during a scratch or bite . Cowpox infection is very rare nowadays. Most cases have been reported in Great Britain and other European countries. In cowpox disease, small number of skin lesions appears on the hands and face.
Initially the site of infection appears as an inflamed flat red lesion (macule). Then, the inflamed lesion becomes raised (papular) and develops into a blister-like sore (vesicle).
Skin ulcer After 2 weeks of the infection, the vesicular rash becomes filled with blood and pus and eventually ulcerates. Other lesions may develop close by. Within next 2-3 weeks, the ulcerated wound turns into a deep-seated, hard, black crusty sore (eschar) which is surrounded by redness and swelling. By 12 weeks, the eschar begins to flake and slough and the lesion heals, often leaving a scar behind. Skin ulcer
After 2 weeks of the infection, the vesicular rash becomes filled with blood and pus and eventually ulcerates. Other lesions may develop close by. Within next 2-3 weeks, the ulcerated wound turns into a deep-seated, hard, black crusty sore (eschar) which is surrounded by redness and swelling. By 12 weeks, the eschar begins to flake and slough and the lesion heals, often leaving a scar behind.
Nonspecific symptoms Fever, malaise, vomiting, lethargy, and sore throat, usually lasting 3-10 days,yet get resolved as ulcerative lesion heals. Nonspecific symptoms
Fever, malaise, vomiting, lethargy, and sore throat, usually lasting 3-10 days,yet get resolved as ulcerative lesion heals.
At risk population Young population in Great Britain and other surrounding European countries are at higher risk. This is possibly due to the fact that younger people may have closer contact with animals such as cats. At risk population
Young population in Great Britain and other surrounding European countries are at higher risk. This is possibly due to the fact that younger people may have closer contact with animals such as cats.

Clinicals - Examination

Fact Explanation
Skin lesion The inoculated site (usually the skin of the hands and face) initially become inflamed and manifest as macular rash. The surrounding area is also erythematous. Within weeks, it becomes a vesiculopapular rash. Vesicle is usually filled with blood. With time, the vesicles are filled with pus. Some of them may ulcerate. The surrounding area may remain erythematous and indurated. A deep-seated, hard, black eschar follows the ulcers. During the final stage, the eschar heals and a scar is left. Lesions may be single or multiple and usually does not itch. Rarely the localized lesions may spread into the rest of the body to form a generalized skin lesions. Skin lesion
The inoculated site (usually the skin of the hands and face) initially become inflamed and manifest as macular rash. The surrounding area is also erythematous. Within weeks, it becomes a vesiculopapular rash. Vesicle is usually filled with blood. With time, the vesicles are filled with pus. Some of them may ulcerate. The surrounding area may remain erythematous and indurated. A deep-seated, hard, black eschar follows the ulcers. During the final stage, the eschar heals and a scar is left. Lesions may be single or multiple and usually does not itch. Rarely the localized lesions may spread into the rest of the body to form a generalized skin lesions.
Eye examination This may rarely reveals conjunctivitis, periorbital edema, and corneal involvement. Eye examination
This may rarely reveals conjunctivitis, periorbital edema, and corneal involvement.
Lymphadenopathy Rarely localized tender lymph node enlargement can be observed. Lymphadenopathy
Rarely localized tender lymph node enlargement can be observed.

Investigations - Diagnosis

Fact Explanation
Electron microscopy Electron microscopic evaluation of vesicle fluid, scab extracts or biopsy specimens may reveal characteristic "mulberry" and "capsule" forms which may diagnostic of Orthopoxviruses. Still the definitive diagnosis of cowpox virus can not be made by this means. Electron microscopy
Electron microscopic evaluation of vesicle fluid, scab extracts or biopsy specimens may reveal characteristic "mulberry" and "capsule" forms which may diagnostic of Orthopoxviruses. Still the definitive diagnosis of cowpox virus can not be made by this means.
Polymerase chain reaction (PCR) PCR may be performed on biopsy material or cell culture. This is diagnostic of cowpox virus. Polymerase chain reaction (PCR)
PCR may be performed on biopsy material or cell culture. This is diagnostic of cowpox virus.
Skin biopsy for histology Immunohistochemistry detects cowpox antigens in infections in cats. Using electron microscopy, biopsy material may reveal viral particles which rarely helps in a differential diagnosis. Skin biopsy for histology
Immunohistochemistry detects cowpox antigens in infections in cats. Using electron microscopy, biopsy material may reveal viral particles which rarely helps in a differential diagnosis.

Management - Supportive

Fact Explanation
Bed rest Patients may feel unwell and require bed rest and supportive therapy. Bed rest
Patients may feel unwell and require bed rest and supportive therapy.
Occlusive bandages Wound dressings or bandages may be applied to lesions to prevent spread to other sites and potentially to other people. Occlusive bandages
Wound dressings or bandages may be applied to lesions to prevent spread to other sites and potentially to other people.
Antiviral medications Antiviral medications are not routinely indicated. Cidofovir, an injectable antiviral medication, can be considered in disseminated cases of cowpox. Antiviral medications
Antiviral medications are not routinely indicated. Cidofovir, an injectable antiviral medication, can be considered in disseminated cases of cowpox.
Antibiotics Topical or systemic antibiotics are only used in case of secondary bacterial infection. Antibiotics
Topical or systemic antibiotics are only used in case of secondary bacterial infection.
Antivaccinia gammaglobulin As most cases are mild and self-limited, usually no treatment is required. However, for severe cases with widespread involvement antivaccinia gammaglobulin may be considered. Antivaccinia gammaglobulin
As most cases are mild and self-limited, usually no treatment is required. However, for severe cases with widespread involvement antivaccinia gammaglobulin may be considered.
Surgical options Surgical treatments other than standard wound dressings are not recommended as they can prolong the infection or spread it to other body sites. Surgical options
Surgical treatments other than standard wound dressings are not recommended as they can prolong the infection or spread it to other body sites.
Prevention Avoiding exposure to sick cats or other sick animals may prevent the infection from the virus.
Recombinant vaccines studied in mice against cowpox may be available for human use in the future.
Prevention
Avoiding exposure to sick cats or other sick animals may prevent the infection from the virus.
Recombinant vaccines studied in mice against cowpox may be available for human use in the future.

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