Poliomyelitis is caused by enterovirus. The incubation period is 7 to 14 days. The communicability period is not exactly known. The virus is present in the throat and feces shortly after the infection and persists for about 1 week in the throat and 4 to 6 weeks in the feces.
The sources of infection are the oropharyngeal secretions and feces of the infected person. Transmission is through direct contact with infected person, fecal-oral and oropharyngeal routes.
The signs and symptoms include abdominal pain followed by soreness and stiffness on the trunk, neck, and limb that progress to flaccid paralysis.
The causative agent of Scarlet fever is group-A beta-hemolytic streptococci. The incubation period is between 1 to 7 days. The communicability period is during the incubation period and clinical illness, about 10 days and during the first 2 weeks of the carrier stage, although it may persist for months.
The sources of infection are nasopharyngeal secretions of infected person and carriers.
The transmission is through direct contact with infected person or droplet spread, indirectly by contact with contaminated articles, and ingestion of contaminated milk or other foods.
The signs and symptoms include abrupt high fever, vomiting, headache, malaise and abdominal pain. Red, fine papular rash develops in the axilla, groin, and neck that spread to cover the entire body. The rash blanches with pressure except in areas of deep creases and folds of the joints called as Pastia’s sign. The tongue is coated and papillae become red and swollen like a white strawberry tongue. By the fourth to fifth day, the white coat sloughs off, leaving prominent papillae or called as red strawberry tongue. The tonsils are edematous or swollen and covered with gray-white exudates. Pharynx is edematous and beefy red.
Infectious Mononucleosis (Kissing Disease)
The kissing disease is caused by Epstein-Barr virus. The incubation period is 4 to 6 weeks. The communicability period is unknown. The virus is shed before the onset of the disease until 6 months or longer after recovery.
The source of infection is the oral secretions. It is transmitted through direct intimate contact or infected blood.
The signs and symptoms include fever, sore throat, malaise, headache, fatigue, nausea and abdominal pain. Lymphadenopathy and hepatosplenomegaly are also present.
The causative agent is Enterobius vernicularis. The sources of infection are the nematodes which is universally present in temperate climatic zones. The eggs are ingested or inhaled since the eggs float in the air, hatches in the upper intestine, mature in 2 to 8 weeks, and migrate to the cecal area. The females then mate, migrate out the anus and lay eggs.
Transmission is favoured in crowded conditions, ingestion of inhalation of eggs, hands to mouth or fecal-oral route and contaminated items. Pinworm eggs persist in the environment for 2 to 3 weeks.
The signs and symptoms include intense peri-anal itching, irritability, restlessness, poor sleep, bed-wetting, distractibility and short attention span. In females, the worm may migrate to the vagina and urethra and cause infection.