Lyme disease (LD) is a vector-borne, multisystem inflammatory disease caused by the spirochete Borrelia burgdoferi sensu lato. It is transmitted to humans by infected ticks of the Ixodes genus. After entering the circulation, the organism invades the cutaneous, synovial, cardiac, and nervous system. Spirochetes have also been demonstrated histologically in bone marrow, the spleen, limph nodes, the liver, testes, and the placenta during early hematogenous dissemination.

Brucellosis is a world-wide zoonosis caused by infection with the bacterial genus Brucella. These organisms, which are small aerobic intracellular coccobacilli, localize in the reproductive organs of host animals, causing abortions and sterility. They are shed in large numbers in the animal's urine, milk, placental fluid, and other fluids. Exposure to infected animals and animal products causes brucellosis in humans. The global burden of human brucellosis remains enormous; it causes more than 500,000 infections per year world-wide. Among the 4 Brucella species known to cause disease in humans (B. abortus, B. melitensis, B. canis, B. suis), B. melitensis is thought to be the most virulent and causes the most severe and acute cases of brucellosis.

Bacillus anthracis is a Gram-positive spore-forming, rod-shaped bacterium, with a width of 1-1.2 µm and a lenght of 3-5 µm. Anthrax was described in the early literature of the Greeks, Romans, and Hindus. Three forms of anthrax disease are recognized based on their form of inoculation: cutaneous - the most common form (95%), causes a localized inflammatory black necrotic lesion (eschar), pulmonary - higly fatal and characterized by sudden massive chest edema followed by cardiovascular shock, gastrointestinal - rare but also fatal (causes death to 25%) type results from ingestion of spores.

Cholera is caused by Vibrio cholerae, the most feared epidemic diarrheal disease because of its severity. Dehydration and death can occur within hours of infection. Robert Koch discovered V cholerae in 1883 during an outbreak in Egypt. The organism is a comma-shaped, gram-negative aerobic bacillus whose size varies from 1-3 µm in lenght by 0.5-0.8 µm in diameter. Its antigenic structure consists of a flagellar H antigen and a somatic O antigen.

Leptospirosis is a world-wide zoonosis caused by pathogenic species of the genus Leptospira. In 90% of cases, leptospirosis manifests as an acute febrile illness with a biphasic course and an excellent prognosis. Nonspecific signs and symptoms of leptospirosis (eg, fever, headache, nausea, vomiting) are often confused with viral illness. In 10% of cases, the presentation is more dramatic, and the infection has a mortality rate of 10%. Known as Weil disease or icteric leptospirosis, the classic definition of this form of leptospirosis includes fever, jaundice, renal failure, and hemorrhage. Other organ system (ie, pulmonary system, cardiac system, CNS) are also frequently involved.

The West Nile virus is one of the many members of the genus Flavivirus that are known to cause human disease. The life cycle of the West Nile virus involves the microbe's transmission from nonhuman animals to humans by way of Aedes, Culex, or Anopheles mosquitoes. The West Nile virus can infect horses, birds, dogs, and other mammals. However, wild birds are apparently the optimal hosts for harboring and replicating the virus. The West Nile virus causes serious manifestations in approximately 1% of persons who are infected, with increased morbidity and mortality in individuals older than 50 years. In hospitalized patients, neurologic sequelae of the West Nile virus included severe muscle weakness, with approximately 10% of patients developing a complete flaccid paralysis. One in 150 West Nile virus infections results in encephalitis or meningitis, and the mortality rate from severe illness is 3-15%.

Q fever is a zoonosis caused by Coxiella burnetii, an obligate gram-negative intracellular bacterium. Most commonly reported in southern France and Australia, Q fever accurs worldwide. C. burnetii infects various hosts, including humans, ruminants (cattle, sheep, goats) and pets. In rare cases, C. burnetii infection in reptilies, birds, and ticks has been reported. C. burnetii is excreted in urine, milk, feces, and birth products. These products, especially the latter, contain large numbers of bacteria that become aerosolized after drying. The bacterium is higly infectious, and only a few organisms can cause disease.

Ticks are arachnids, relatives of spiders that commonly live in woodes areas, brushy fields. They survive by eating blood from their host and they can pass infections from one host to another, including humans. Common tick-borne diseases are: Tick-Borne Encephalitis (TBE), Anaplasmosis, Ehrlichiosis.

Congo-Crimea hemorrhagic fever is a widespread tick-borne viral disease, a zoonosis of animals that may affect humans. The pathogenic virus, commonly present in East and West Africa, is a member of the Bunyaviridae family of RNA viruses. Clinical disease is rare in infected mammals, but commonly severe in infected humans, with a 30% mortality rate.

Pyogenic refers to bacterial infections that make pus, that is destryed by bacteria such as Streptococcus pyogenes and Staphylococcus aureus through the release of leukocidins. Methicillin-resistant Staphylococcus aureus (MRSA) is a strain of Staphylococcus aureus that has developed resistance to beta-lactam antibiotics which include the penicillins (oxacillin, methicillin, dicloxacillin, nafcillin, etc.) and the cephalosporins. Resistance does make MRSA infection more difficult to treat with standard types of antibiotics.

Dengue is one of the most important arthropod-borne viral diseases with large global burden. The
disease is caused by dengue virus (DENV), a member of Flaviviridae family, with four distinct
serotypes (DENV-1, -2, -3, and -4) circulating in tropical and subtropical regions in the world.
DENV is transmitted to human by Aedes mosquitoes as vector. Dengue clinical manifestations
vary from asymptomatic or mild flu-like syndrome known as classic Dengue Fever (DF) to more
severe form known as Dengue Hemorrhagic Fever (DHF) and the potentially fatal Dengue Shock
Syndrome (DSS). Similar to other RNA viruses, DENV possess diverse genetic characteristics as
shown by the presence of various genotypes within serotypes.

Ebola virus (EBOV, formerly designated Zaire ebolavirus) is the sole member of the Zaire ebolavirus species, and the most dangerous of the five known viruses within the genus Ebolavirus.

Yersinia pestis is a Gram-negative rod-shaped bacterium. It is facultative anaerobe able to infect humans and other animals. Many evidence suggest that it was a contributing factor in many plagues throughout human history. The reservoir commonly associated with Y. pestis are several species of rodents (marmot, rats).

Zika virus (ZIKV) is a member of the virus family Flaviviridae and the genus Flavivirus. It is spread by daytime-active Aedes mosquitoes, such as A. aegypti and A. albopictus. Its name comes from the Zika Forest of Uganda, where the virus was first isolated in 1947