Infectious diseases
List of major infectious diseases
Hepatitis A: viral disease that interferes with the functioning of the liver; spread
through consumption of food or water contaminated with fecal matter, principally
in areas of poor sanitation; victims exhibit fever, jaundice, and diarrhea; 15% of
victims will experience prolonged symptoms over 6-9 months; vaccine available.
Hepatitis E: water-borne viral disease that interferes with the functioning of the liver;
most commonly spread through fecal contamination of drinking water; victims exhibit
jaundice, fatigue, abdominal pain, and dark colored urine.
Typhoid fever: bacterial disease spread through contact with food or water contaminated
by fecal matter or sewage; victims exhibit sustained high fevers; left untreated,
mortality rates can reach 20%.
Vectorborne diseases acquired through the bite of an infected arthropod:
Malaria: caused by single-cell parasitic protozoa Plasmodium; transmitted to humans via the
bite of the female Anopheles mosquito; parasites multiply in the liver attacking red blood
cells resulting in cycles of fever, chills, and sweats accompanied by anemia; death due
to damage to vital organs and interruption of blood supply to the brain; endemic in 100,
mostly tropical, countries with 90% of cases and the majority of 1.5-2.5 million
estimated annual deaths occurring in sub-Saharan Africa.
Dengue fever: mosquito-borne (Aedes aegypti) viral disease associated with urban environments;
manifests as sudden onset of fever and severe headache; occasionally produces shock and
hemorrhage leading to death in 5% of cases.
Yellow fever: mosquito-borne viral disease; severity ranges from influenza-like symptoms to s
evere hepatitis and hemorrhagic fever; occurs only in tropical South America and sub-Saharan Africa,
where most cases are reported; fatality rate is less than 20%.
Japanese Encephalitis: mosquito-borne (Culex tritaeniorhynchus) viral disease associated with
rural areas in Asia; acute encephalitis can progress to paralysis, coma, and death; fatality rates 30%.
African Trypanosomiasis: caused by the parasitic protozoa Trypanosoma; transmitted to humans via
the bite of bloodsucking Tsetse flies; infection leads to malaise and irregular fevers and, in
advanced cases when the parasites invade the central nervous system, coma and death;
endemic in 36 countries of sub-Saharan Africa; cattle and wild animals act as reservoir hosts for the parasites.
Cutaneous Leishmaniasis: caused by the parasitic protozoa leishmania; transmitted to humans via
the bite of sandflies; results in skin lesions that may become chronic; endemic in 88 countries;
90% of cases occur in Iran, Afghanistan, Syria, Saudi Arabia, Brazil, and Peru; wild and
domesticated animals as well as humans can act as reservoirs of infection.
Plague: bacterial disease transmitted by fleas normally associated with rats; person-to-person
airborne transmission also possible; recent plague epidemics occurred in areas of Asia, Africa,
and South America associated with rural areas or small towns and villages; manifests as fever,
headache, and painfully swollen lymph nodes; disease progresses rapidly and without antibiotic
treatment leads to pneumonic form with a death rate in excess of 50%.
Crimean-Congo hemorrhagic fever: tick-borne viral disease; infection may also result from exposure
to infected animal blood or tissue; geographic distribution includes Africa, Asia, the Middle East,
and Eastern Europe; sudden onset of fever, headache, and muscle aches followed by hemorrhaging in
the bowels, urine, nose, and gums; mortality rate is approximately 30%.
Rift Valley fever: viral disease affecting domesticated animals and humans; transmission is by
mosquito and other biting insects; infection may also occur through handling of infected meat or
contact with blood; geographic distribution includes eastern and southern Africa where cattle and
sheep are raised; symptoms are generally mild with fever and some liver abnormalities, but the
disease may progress to hemorrhagic fever, encephalitis, or ocular disease;
fatality rates are low at about 1% of cases.
Chikungunya: mosquito-borne (Aedes aegypti) viral disease associated with urban environments,
similar to Dengue Fever; characterized by sudden onset of fever, rash, and severe joint pain
usually lasting 3-7 days, some cases result in persistent arthritis.
Water contact diseases acquired through swimming or wading in freshwater lakes, streams, and rivers:
Leptospirosis: bacterial disease that affects animals and humans; infection occurs through contact
with water, food, or soil contaminated by animal urine; symptoms include high fever, severe headache,
vomiting, jaundice, and diarrhea; untreated, the disease can result in kidney damage, liver failure,
meningitis, or respiratory distress; fatality rates are low but left untreated recovery can take months.
Schistosomiasis: caused by parasitic trematode flatworm Schistosoma; fresh water snails act as
intermediate host and release larval form of parasite that penetrates the skin of people exposed
to contaminated water; worms mature and reproduce in the blood vessels, liver, kidneys, and
intestines releasing eggs, which become trapped in tissues triggering an immune response; may
manifest as either urinary or intestinal disease resulting in decreased work or learning capacity;
mortality, while generally low, may occur in advanced cases usually due to bladder cancer;
endemic in 74 developing countries with 80% of infected people living in sub-Saharan Africa;
humans act as the reservoir for this parasite. aerosolized dust or soil contact disease acquired through
inhalation of aerosols contaminated with rodent urine:
Lassa fever: viral disease carried by rats of the genus Mastomys; endemic in portions of West Africa;
infection occurs through direct contact with or consumption of food contaminated by rodent urine or fecal
matter containing virus particles; fatality rate can reach 50% in epidemic outbreaks.
respiratory disease acquired through close contact with an infectious person:
Meningococcal meningitis: bacterial disease causing an inflammation of the lining of the brain and spinal
cord; one of the most important bacterial pathogens is Neisseria meningitidis because of its potential
to cause epidemics; symptoms include stiff neck, high fever, headaches, and vomiting; bacteria are
transmitted from person to person by respiratory droplets and facilitated by close and prolonged contact
resulting from crowded living conditions, often with a seasonal distribution; death occurs in 5-15% of cases,
typically within 24-48 hours of onset of symptoms; highest burden of meningococcal disease occurs in the
hyperendemic region of sub-Saharan Africa known as the "Meningitis Belt" which stretches from Senegal east to Ethiopia.
Animal contact disease acquired through direct contact with local animals:
Rabies: viral disease of mammals usually transmitted through the bite of an infected animal, most commonly dogs;
virus affects the central nervous system causing brain alteration and death; symptoms initially are non-specific
fever and headache progressing to neurological symptoms; death occurs within days of the onset of symptoms.
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