Scarlet fever

Scarlet fever (known as scarlatina in older literature references) is an infectious disease caused by bacteria called Streptococcus pyogenes, or group A streptococcus (GAS) can colonize the throat or the skin. The same bacteria can also cause impetigo.

Scarlet fever is a syndrome characterized by a rash, which usually accompanies a sore throat. It can have complications, and it needs to be recognized at presentation as it is a notifiable disease.

The rash is the most striking sign of scarlet fever. This is a scarlet, confluent rash, mainly macular (flat) rather than papular (bumpy).

Transmission occurs by direct person-to-person contact via saliva or nasal secretions or, rarely, by indirect contact through objects or hands. The incubation period is two to five days.

Bacteria that cause the infection produce toxins (poisons), which cause the rash, a red and swollen tongue and flushed cheeks. The scarlet fever rash can be confused with measles.

Scarlet fever is mainly a childhood disease and is most commonly seen between the ages of 2 and 8 years. Unlike many infectious diseases seen in children, is not vaccine preventable. Although historically considered a dangerous disease, it is now much less serious.

Scarlet fever is highly contagious and, if not treated with antimicrobials, can be infectious for two to three weeks after the onset of symptoms.
Scarlet fever

What is syphilis?

Syphilis was initially described in Europe in the latter part of the fifteenth century. Its origin remains shrouded in mystery. Syphilis is an infection caused by the bacterium Treponema pallidum.

T. pallidum is a long, slender, coil-shaped organism that measures 6-15 μm in length but only 0.15 μm in width, a dimension below the resolution of light microscopy. The organism has regular spirals numbering 5-20 and is actively motile, using a rotational screw-like activity, flexion and back and-forth motion.

It invades the body through the mucous membranes of the genitals and if untreated leads to physical damage and mental problems. Syphilis is currently is of particular concern because it is believed to increase the transmission of HIV.

Syphilis is caused by unprotected sexual contact with an infected person. The first signs appear about three weeks after contact, but the interval (incubation period) may be as short as 10 days or as long as three months.

If syphilis remains untreated the disease may go into the latent stage. People at this point usually have no further signs or symptoms of disease. Syphilis like many sexually transmitted disease, can be prevented by practicing safe sex and using latex condoms properly and consistently.
What is syphilis?

Bubonic plague

In the late 1800s, researchers discovered that plague is caused by a type of bacteria called Yersinia pestis. The bacteria love in the bodies of fleas that normally make their home in the fur of rats and other rodents.

Yersinia pestis is a motile, pleomorphic, and gram negative bacterium of the bacillus type.  It protects itself well after encountering an animal’s immune system but does not last long in the open environment.

The name by which the bubonic plague came to be known was related to the formation of black boils in the armpits, neck and groin of infected people, which were caused by dried blood accumulating under the skin internal bleeding.

Bubonic plague is naturally a disease of animals. It jumps to human, becoming a zoonosis. Fleas infected with plague carry the bacteria in their digestive systems. When they bite a human, the bacteria are released into the human’s body and travel to the lymph nodes.

At this time, a victim begins suffering from a fever, headaches and muscle pain. Then two to six days after being infected, the person’s lymph nodes become swollen.

If untreated, it often is fatal to humans. Treatment is accomplished by application of antibiotics , often streptomycin, but early detection in important. Most victims died horribly, shortly after symptoms appeared.
Bubonic plague

What is Lyme disease in human?

Symptoms that almost certainly represent cases of Lyme disease were described in the European medical literature in the late nineteenth century.

A resident of Lyme, Connecticut, named Polly Murray, who is credited with original detective work that alerted biomedical experts that anew disease might exist, probably suffered from Lyme disease as early as the 1950s.

The discoveries that led to the contemporary view of this infectious disease occurred in 1982, when Willy Burgdorfer and his colleagues identified what turned out to be a new Borrelia species from Ixodes ticks collected on eastern Long Island.

Lyme disease is a bacterial infection caused by Borrelia Burgdorferi, and elongated, spiral-shaped bacteria transmitted to humans through the bite of a tick.

Known as spirochetes, these bacteria are unusual, not well studied, elusive and difficult to cultivate in the laboratory, and capable of advanced survival activities more commonly found in larger, more intelligent organisms.

The ailment, which affects adults and children alike, is widespread in the northern hemisphere and continues to expand as humans encroach in the sylvatic habitat of the spirochete’s mammalian reservoirs.

Early symptoms of the disease in humans include muscle aches, low-grade fever, and lethargy; these are followed later by arthritis and damage to the heart and nervous system.
What is Lyme disease in human?