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Germs that infect humans


Haemophilus influenzae

Haemophilus influenzae

© Illustration Bruno Laporte

Microorganism: Epstein-Barr virus (EBV)

Disease: mononucleosis

Occurrence of the disease

Mechanism of action of the microorganism: the virus enters the lymphatic tissue and infects the B cells of the immune system. The infected cells multiply and take on a characteristically deformed appearance that allows diagnosis of the disease.

The Epstein-Barr virus also causes Burkitt’s lymphoma, a malignant tumor. This was the first type of cancer to be associated with a viral infection.

Symptoms of the disease: enlargement of the lymph nodes and spleen, sore throat, headache, nausea, and generalized fatigue.

Incubation period: four to six weeks

Contagious period: if the virus remains in the secretions of the pharynx, contagious period may persist for more than one year.

Host: humans

Transmission: this disease, which is not highly contagious, can be transmitted from mouth to mouth – hence the name “kissing disease.”

Treatment: none. Rest is generally recommended.

Geographical distribution of the microorganism: worldwide

Prevention: avoid contact with sick persons

Vaccine: not available