House Mouse

Mus Domesticus

Appearance The colour of mouse fur varies between light brown and grey. The body length varies between 6 and 9cm and the tail can add an additional 10cm. Mouse droppings are black, rod-shaped and between 3 and 6mm long. Lifecycle Mice are adaptable, highly mobile and breed rapidly. Their gestation period is about 19-21 days. After gestation, they give birth to a litter of 3-14 young (average 6-8). One female can have 5-10 litters per year. Females reach sexual maturity at about 6 weeks and males at about 8 weeks.

Habits

Mice are mainly active at night. While a mouse can squeeze through a crack as small as 5mm, a typical mouse hole would normally be 2-3cm in diameter. Nests are built wherever there is access to a good source of food. Favourite foods are cereal products, although they will eat almost anything. Mice consume about 3g of food and up to 3ml of water per day if their diet is very dry. Over a 6 month period, a pair of mice will produce about 18,000 droppings and 340g (12oz) of urine.

Disease

Mice carry various diseases including: Infectious jaundice, Lymphocytic choriomeningitis, St. Louis Encephalitis, Hantavirus Pulmonary Syndrome, and Murine Typhus.

Tapeworms are transmitted via food contaminated with droppings.

Rickettsialpox - a disease characterized by fever, chills, headache, backache, and a spotty rash, caused by a bacterium of the genus Rickettsia transmitted to humans by the bite of a mite of the genus Allodermanyssus living on rodents such as the house mouse.

Rat-bite fever (RBF) is a systemic bacterial illness caused by Streptobacillus moniliformis and Spirillum minus that can be acquired through the bite or scratch of a rodent (ie: rat or mouse) or the ingestion of contaminated food or water from infected faeces. Symptoms usually occur 2-10 days after exposure to an infected animal. Common symptoms include an abrupt onset of chills and fever, vomiting, pain in the back and joints, headache and muscle pain. By this time, the wound itself has usually already healed. Within 2-4 days after the onset of fever, a rash appears on the hands and feet. One or more large joints may then become swollen, red, and painful. Often clinical signs subside in several days but then recur at irregular intervals for weeks or months.

Salmonellosis - bacterial food poisoning caused by bacteria of the genus Salmonella. Characterized by diarrhoea that will last about ten days, abdominal cramps, vomiting and nausea. Unfortunately, in the elderly, young, or people with depressed immune systems, Salmonella infections are often fatal if they are not treated with antibiotics. but often complicated by septicaemia, meningitis, endocarditis, and various focal lesions (as in the kidneys) when food is contaminated with infected rodent faeces.

Yersinosis is an infection by a genus of bacteria known as Yersinia which has an incubation period of 1-11 days. Symptoms include acute watery diarrhea, mesenteric lymphadenitis which can be confused with appendicitis, fever, headache, pharyngitis, anorexia, vomiting erythema nodosum (in about 10% of adults), post-infectious arthritis, iritis, cutaneous ulceration, hepatosplenic abscesses, osteomyelitis and septicemia. Cramping abdominal pain, fever, and diarrhea which may last for two weeks or so, but can go on for many months. Yersinia may also produce an inflammation of the throat (pharyngitis) and tonsillitis. Septicemia may also occur, with spreading of infection to other organs such as bone, joints, eyes, urinary system and kidneys. Symptoms can be very severe, resulting in death.

Pseudotuberculosis (Corynebacteriosis) is a common and deadly infectious disease caused by mycobacteria, mainly Mycobacterium tuberculosis. Tuberculosis most commonly attacks the lungs (as pulmonary TB) but can also affect the central nervous system, the lymphatic system, the circulatory system, the genitourinary system, bones, joints and even the skin.

Leptospirosis - Weil's disease - is caused by bacteria of the genus Leptospira, and is transmitted by the urine of an infected animal. In humans it causes a wide range of symptoms including high fever, severe headache, chills, muscle aches, and vomiting, and may include jaundice (yellow skin and eyes), red eyes, abdominal pain, diarrhea, or a rash. If the disease is not treated, the patient could develop kidney damage, meningitis (inflammation of the membrane around the brain and spinal cord), liver failure, and respiratory distress. Humans become infected through contact with water, food, or soil containing urine from these infected animals. This may happen by swallowing contaminated food or water or through skin contact. Symptoms appear after a 4-14 day incubation period. Up to 50% of severe leptospirosis cases are fatal.

Borreliosis - Lyme Disease - Caused by the bacteria Borrelia recurrentis and several other borrelia strains spread from wild rodents by deer ticks or lice. Lyme disease can attack the skin, heart and nervous system and cause swelling to the brain and spinal cord resulting in paralysis and blindness. The early symptoms can be similar to severe flu and often it's wrongly diagnosed. Incubation is from 1-15 days. Symptoms include the sudden onset of fever lasting for 3-5 days, ends with a crisis. Then a febrile period of 2-4 days is followed by one to ten or more recurrences of fever accompanied by severe headaches, nausea, vomiting, diarrhoea, jaundice and sometimes a macular rash with bleeding due to thrombocytopenia. Many lesions occur, including enlarged, soft, infarcted spleen, hepatomegaly, hemorrhages in bone marrow and skin, myocarditis, bronchopneumonia, and meningitis. Cranial nerve involvement is possible. Also flu like symptoms, which resolve in about three weeks. 8-10% of people develop cardiac problems several weeks later.

Manifestations include atrioventricular block, cardiomyopathy, heart failure, myocarditis, and pancarditis. 15% develop neurologic disorders such as facial nerve palsies which usually resolve. Other manifestations include meningitis, cranial neuritis, radiculoneuritis, neuropathy, and encephalopathy. 60% develop arthritis which may remain latent with symptoms developing 4 years later. Most cases of Lyme disease can be treated successfully with a few weeks of antibiotics. Most cases of Lyme disease can be treated successfully with a few weeks of antibiotics.

Psittacosis - Transmission is usually by inhalation of dry feces which produce highly infective aerosols. Direct contact with feces or respiratory secretions may also be a vector of infection. May survive in dust for several months. 1-2 week incubation period. Fever, chills, myalgia, anorexia, headache, nonproductive cough. Pneumonitis or atypical pneumonia may be present. May see a toxic or septic form with hepatosplenomegaly, hepatitis, meningoencephalitis and cardiac involvement with endocarditis. Ovine chlamydial infection in pregnant women is life-threatening, causing late abortion and neonatal death and disseminated intravascular coagulation in the mother.

Toxoplasmosis - (Toxoplasma dondi) is an infection that invades human tissue and can severely damage the central nervous system, especially in babies. Pregnant women are in extreme danger if infected. Toxoplasmosis occurs in humans usually as low-grade fever or muscle pain for a few days. A normal immune system will suppress the infection but the tissue cysts can persist in the host for many years. In immunocompromised individuals, those dormant cysts can be reactivated and cause many lesions in the brain, heart, lungs, eyes, etc. Without a competent immune system, the animal or human will most likely die from the infection.