Monkeypox is a virus, similar to smallpox but milder. It is infectious to all animal species, including humans, and has a death rate of up to 10 percent. The smallpox vaccine is said to work well against monkeypox. ¹⁾

It's estimated that 59,000 people die from rabies every year worldwide, mainly in Africa and Asia. Once symptoms appear, the fatality rate is nearly 100 percent as there are no effective treatment options, even with intensive care. As of 2016, there are only 14 cases in the history of people who survived rabies after showing symptoms. However, thanks to the vaccine developed by Louis Pasteur in 1885, it's possible to avoid disease in 100 percent of cases if the vaccine is given within 10 days of exposure. ²⁾

Shigella is a type of Gram-negative bacteria that causes dysentery. The only reservoirs of the bacteria are humans and monkeys. The bacteria were first isolated and described in 1897 by the Japanese microbiologist Kiyoshi Shiga. ³⁾

Chagas disease or American trypanosomiasis, is extremely dangerous to the human body. It is caused by a parasite from the mumps family called trypanosoma cruzi. This parasite is transmitted to humans through insects such as, for example, bugs, which can be found under different names in various countries. Sometimes the disease can also be transmitted to humans by animals, such as possums or armadillos, and sometimes rodents. These animals like to stay in polluted areas, near garbage dumps. Theoretically, the disease is not strongly life-threatening in its first phase as far as adults are concerned, but it can cause deaths in infants, for example. ⁴⁾

The cause of plague infections is bacterial bacilli carried by fleas. These insects “live” on the body of rodents such as rats and mice, as these are the animals most often found in contaminated areas where basic hygiene is lacking. In the Middle Ages, the plague reached epidemic proportions, infecting many thousands of people, and thus leading humanity to death. Humans are most often infected through the bite of a flea, which gets on them from the animal's body. Importantly, the extraordinary popularization of the disease led to the plague being used as a biological weapon. In the 14th century, the Tartars used the plague to infect other people, causing the disease to spread throughout Europe, leading to quite a bit of human plague. Plague can also be contracted through the droplet route, in which case it is said to be the pulmonary variant of this dangerous disease. This type of disease attacks the lymph nodes. Plague hatches in the human body relatively quickly, as from 2 to 10 days. ⁵⁾

Characteristic symptoms that indicate the onset of Japanese encephalitis are speech problems and pain when urinating, known as dysuria. The incubation period of this disease is one to two to three weeks. It is worth noting that tourists are particularly vulnerable to this disease, as they do not have the same immunity as natives. Although the disease is usually not aggressive and dangerous to the human body, it is worth not underestimating the prolonged symptoms of the disease, especially if there is pain when urinating or speech problems. It is a good idea to visit a specialist in such cases. If left untreated, the disease can lead to complications such as encephalitis or meningitis, nerve damage, impaired consciousness, severe paresis, muscle weakness, ataxia, and parkinsonism. In extreme cases, the disease can even lead to death. ⁶⁾

The incubation period for this disease is up to several months. It is the most dangerous variety of leishmaniasis, as it attacks human organs. The most characteristic symptom of this disease is a sudden and bipolar high fever, which usually strikes around noon and around midnight. The fever can reach up to 40 degrees. The initial symptoms resemble the flu, but after a while there is rapid weight loss and enlargement of the spleen and liver, lymph nodes. In addition, the patient begins to develop petechiae and skin lesions, turning into open wounds. The lesions appear around the face and hands. Initially, there is exfoliation of the epidermis, which leads to the formation of severe ulcerations and open wounds. Unfortunately, as many as 90, 95% of patients who receive treatment too late, or no treatment at all, die. Infections of the gastrointestinal tract, internal organs, osteomyelitis or meningitis usually occur. Tuberculosis is also a very characteristic symptom. Visceral leishmaniasis can be confused with typhoid fever or malaria. ⁷⁾

Noma colloquially known as water cancer, is a disease caused by bacteria from the Fusobacterium family. It attacks the face, as it is a gangrenous inflammation of the oral mucous membranes. The patient develops a cachexia of the lips, cheeks and nasal mucous membranes. The condition leaves a person permanently disfigured, as it gets rid of a portion of the face and teeth. Noma is very common in extremely malnourished people with low immunity. Usually in children and infants under the age of 7. The word “noma” comes from the Greek (neimen) and means, literally devouring. The disease “devours” the human face, causing permanent and irreversible damage to health. It is also very often a complication of diseases such as HIV, AIDS and measles. The official name was introduced in 1816. ⁸⁾

River blindness, or onchocerciasis, is an extremely dangerous disease, as it often causes permanent disability, the patient may become blind for life. A person is infected by being bitten by insects known as “mossy bugs,” which live among swift waters or fast-flowing river streams. Hence the disease owes its second, quite common name - river blindness. Once infected, parasites develop in the human body, which can take up to a year to mature! The adults migrate to the eyes, permanently damaging vision. Onchocerciasis is the second most common pathological cause of vision loss in the world, just ahead of the only one, jaggery. Interestingly, female onchocerciasis larvae can live in the human body for up to 15 years, producing and multiplying new individuals. River blindness is considered an extremely dangerous disease. ⁹⁾

Typhoid fever is a disease that is caused by a bacterium: rickettsia prowazekii, commonly known as rickettsia. It is worth noting that it is a typically zoonotic disease, which is transmitted by lice and fleas. It can be categorized as a disease that occurs in heavily populated areas, as well as polluted areas. Thus, it mainly occurs in the territories of Africa, Asia, or South America. A fair number of cases can still be recorded in these territories. This is mainly due to the fact that these are areas where high temperatures prevail, which favor the proliferation of the bacteria. Spotted typhus is primarily the result of a lack of hygiene and ubiquitous dirt. Although Europe is not dominated by heavily polluted areas, spotted typhus can sometimes be encountered, so extreme caution should be exercised, mainly when dealing with people such as the homeless. Lice and fleas can also linger in places or even facilities that are contaminated, and in those where rats are present. They are largely responsible for the transmission of this contagious disease. ¹⁰⁾

West Nile Virus (WNV) is part of the Japanese Encephalitis antigenic complex and belongs to the Flavivirus family of Flaviviridae. This virus most often develops in countries where warm and humid climates prevail. Interestingly, therefore, it can be encountered in Poland, but quite rarely, mainly during the season of highest mosquito activity, i.e. in summer. Recently, several fatal cases of the virus have been confirmed in Greece. Two elderly people have died, suffering from West Nile Fever, which is caused by this virus. Many people were taken to hospitals. West Nile Virus is a contagious condition that causes specific symptoms. Unfortunately, the elderly or children are very often the fatal victims of this virus, mainly because they do not have as good immunity, resulting in many unwanted complications, such as acute hepatitis or pancreatitis. The reservoir is mainly birds, which infect mosquitoes. In animals and humans, the disease can be asymptomatic. ¹¹⁾

Bartonellosis can be contracted through direct contact with insects, namely mosquitoes, fleas or ticks, as well as through contact with wild and domestic animals. The reservoir can therefore be both dogs and cats, living in the home. Most importantly, Bartonellosis is contracted when an animal or insect infected with the bacterium bites or scratches. Currently, Bartonellosis is caused by as many as 24 types of bartonella bacteria, many of which are also pathogenic to humans. It is worth noting that the first carriers are fleas, mosquitoes or ticks. They can scratch or bite animals, even those indoors. Pets, such as cats, dogs, bitten by insects, infected with bartonella, can “pass” the disease to humans. Diseases in the Bartonellosis family include, among others, the rather popular cat claw disease. ¹²⁾

There are four serological types of this virus: DENV-1, DENV-2, DENV-3, DENV-4. Mosquitoes of the Flavivirdae Aedes family are the reservoir of Dengue. Epidemiological studies on the spatial boundaries of Dengue virus transmission have shown that 3.8 billion people in 129 countries are currently exposed to the infection. According to data reported by the WHO, Dengue fever is now the fastest spreading mosquito-borne disease. Between 50 and 390 million people worldwide are sickened annually,and half a million are hospitalized. They attack mainly on the Asian continent and can be found in South and East Asia ( in such popular countries as Thailand, Cambodia, Vietnam, Laos, Philippines, Indonesia, India, Malaysia, Sri Lanka ). Very many cases of the disease are also reported in Africa ( Egypt, Kenya, Tanzania plus Zanzibar ), America ( Dominican Republic, Argentina, Brazil, Jamaica, Cuba, Mexico ). The development of Aedes mosquitoes is favored by a very tropical climate. Hence the proliferation of these mosquitoes in this part of the hemisphere. Interestingly, it is also possible to record cases of Dengue disease in Europe! including on the island of Madeira in Portugal or Spain and other areas of the Mediterranean. This situation is certainly influenced by the fact of an increasingly warming climate and the establishment of mosquitoes in the area. Dengue can also spread through blood transfusion or organ transplantation. Special caution should be exercised by young children, in whom the course of this disease can be really severe, and pregnant women. ¹³⁾

Loaiosis is otherwise known as loa loa disease. Infection occurs through the bite of two types of flies: Chrysops silacea and Chrysops dimidiata. The parasites enter the human bloodstream to then begin the process of feeding on the human body. Interestingly, these larvae can move throughout the body, manifesting themselves as a variety of cysts on the body. The nematode larvae mature only in the human body, as it is their last host. Adult specimens are quite sizable, with females reaching a length of 40 to 70 mm, and males 30 to 34 mm. The cross section of these larvae can also be quite large, as females usually measure 0.5 millimeters in circumference. The life cycle of these parasites is extremely elaborate, as the larvae lay eggs all the time, forming microfilariae that travel throughout the human bloodstream. They can also be found in cerebrospinal fluid, saliva and even urine! ¹⁴⁾

Zika virus (ZIKV) belongs to the Flaviviridae family (known as flaviviruses), which also includes other pathogenic pathogens such as yellow fever virus and dengue virus. It first appeared in Uganda most likely between 1892 and 1943 in various species of monkeys. Replication of the virus took place in mosquito → monkey → mosquito cycles, and in 1951 the first human cases were found. Since May 2015, an increase in cases has been observed primarily in South America, Central America and the Caribbean. In the European part of the globe, isolated cases of the virus have been detected in Spain, Germany, France and Austria. The infections involved people who temporarily stayed in areas endemic to the pathogen and then returned to their place of residence. Poland is considered to be free of the virus, although in earlier years there were reports of several people returning from foreign travel being infected. ¹⁵⁾

One of the more dangerous infectious, viral diseases can include chikungunya virus. This disease is also commonly known as chikungunya fever or chikungunya virus. It causes general fatigue and exhaustion of the body, as well as chronic inflammation of joints and muscles and bone pain. Although on the surface it may seem otherwise, unfortunately, viral diseases are extremely invasive to humans. They are usually caused by viruses that are carried by animals or found in infected food. Unfortunately, one may not always realize that one is just getting infected. The same is precisely the case with chikungunya disease. ¹⁶⁾