Sodoku is a bacterial zoonotic disease. It is caused by outnumbered spirochaete

Spirochaete

Spirochaetes belong to a phylum of distinctive Gram-negative bacteria, which have long, helically coiled cells...

 Spirillum minus

Spirillum minus

Spirillum minus is a species of Spirillum.Spirillum minus is associated with rat-bite fever....

. It is a form of rat-bite fever

Rat-bite fever

Rat-bite fever is an acute, febrile human illness caused by bacteria transmitted by rodents, rats in most cases, which is passed from rodent to human via the rodent's urine or mucous secretions. Alternative names for rat bite fever include streptobacillary fever, streptobacillosis, spirillary...

 (RBF).

Causes

The infections are acquired through rat

Rat

Rats are various medium-sized, long-tailed rodents of the superfamily Muroidea. "True rats" are members of the genus Rattus, the most important of which to humans are the black rat, Rattus rattus, and the brown rat, Rattus norvegicus...

 bites or scratches. It can occur as nosocomial infections (ie, acquired from hospitals), or due to exposure or close associations with animals preying on rats, mice, squirrels etc. Sodoku is mostly seen in Asia. The incubation period is 4 to 28 days.

Presentation and symptoms

The initial scratch or wound caused by a bite from a carrier rodent will result in mild inflammatory reactions and ulcerations. The wounds may heal initially, but reappear with the onset of symptoms. The symptoms include recurring fever

Fever

Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...

, with body temperature 101–104 °F (38–40°C). The fever lasts for 2–4 days but recur generally at 4–8 weeks. This cycle may continue for months or years together. The other symptoms include regional lymphadenitis, malaise

Malaise

Malaise is a feeling of general discomfort or uneasiness, of being "out of sorts", often the first indication of an infection or other disease. Malaise is often defined in medicinal research as a "general feeling of being unwell"...

 and headache

Headache

A headache or cephalalgia is pain anywhere in the region of the head or neck. It can be a symptom of a number of different conditions of the head and neck. The brain tissue itself is not sensitive to pain because it lacks pain receptors. Rather, the pain is caused by disturbance of the...

. The complications include myocarditis

Myocarditis

Myocarditis is inflammation of heart muscle . It resembles a heart attack but coronary arteries are not blocked.Myocarditis is most often due to infection by common viruses, such as parvovirus B19, less commonly non-viral pathogens such as Borrelia burgdorferi or Trypanosoma cruzi, or as a...

, endocarditis

Endocarditis

Endocarditis is an inflammation of the inner layer of the heart, the endocardium. It usually involves the heart valves . Other structures that may be involved include the interventricular septum, the chordae tendineae, the mural endocardium, or even on intracardiac devices...

, hepatitis

Hepatitis

Hepatitis is a medical condition defined by the inflammation of the liver and characterized by the presence of inflammatory cells in the tissue of the organ. The name is from the Greek hepar , the root being hepat- , meaning liver, and suffix -itis, meaning "inflammation"...

, splenomegaly

Splenomegaly

Splenomegaly is an enlargement of the spleen. The spleen usually lies in the left upper quadrant of the human abdomen. It is one of the four cardinal signs of hypersplenism, some reduction in the number of circulating blood cells affecting granulocytes, erythrocytes or platelets in any...

 and meningitis

Meningitis

Meningitis is inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. The inflammation may be caused by infection with viruses, bacteria, or other microorganisms, and less commonly by certain drugs...

.

Prognosis

Mortality

Mortality rate

Mortality rate is a measure of the number of deaths in a population, scaled to the size of that population, per unit time...

ranges from 6-10%.