Iraq's Major Infectious Diseases
Food or waterborne diseases acquired through eating or drinking on the local economy:
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.
Symptoms of hepatitis A
You can fall ill any time between 15 and 50 days after catching the virus. The average incubation period for the virus is 28 days. Many infected people, particularly children less than five years old, show few or no symptoms.
For older children and adults, the symptoms include:
Complications of hepatitis A
Relapses of hepatitis A occur in around 10 per cent of cases, although people who have relapses fully recover. Hepatitis A does not cause chronic liver disease.
Complications of hepatitis A are rare but the infection can lead to fulminant hepatitis, which is an acute form of hepatitis that can cause liver failure. The risk of death from fulminant hepatitis increases with age.
Causes of hepatitis A
Hepatitis A is caused by a virus. The virus can survive for several hours outside the body but persists on the hands and in food for even longer and is resistant to heating and freezing.
The virus is spread when it enters the mouth, which can happen when hands, foods or other items are contaminated with the faeces of a person with hepatitis A. The disease can also be spread sexually by oral–anal contact. A person with hepatitis A is infectious from two weeks before they show symptoms to one week after they become jaundiced.
Reducing the risk of hepatitis A
Practising strict personal hygiene is essential to reducing the risk of hepatitis A. Steps you can take include:
Careful selection and preparation of food and drink is vital and suggestions include:
Tests used to diagnose hepatitis A may include:
There is no specific treatment for hepatitis A. In most cases, your immune system will clear the infection and your liver will completely heal. Treatment aims to ease symptoms and reduce the risk of complications. Options may include:
Signs and symptoms
Acute infection
The incubation period of hepatitis E varies from 3 to 8 weeks. After a short prodromal phase symptoms lasting from days to weeks follow. They may include jaundice, fatigue and nausea. The symptomatic phase coincides with elevated hepatic aminotransferase levels.
Viral RNA becomes detectable in stool and blood serum during incubation period. Serum IgM and IgG antibodies against HEV appear just before onset of clinical symptoms. Recovery leads to virus clearance from the blood, while the virus may persist in stool for much longer. Recovery is also marked by disappearance of IgM antibodies and increase of levels of IgG antibodies.
Chronic infection
While usually an acute disease, in immunocompromised subjects—particularly in solid organ transplanted patients—hepatitis E may cause a chronic infection.Occasionally this may cause liver fibrosis and cirrhosis.
Transmission
Hepatitis E is prevalent in most developing countries, and common in any country with a hot climate. It is widespread in Southeast Asia, northern and central Africa, India, and Central America. It is spread mainly by the fecal-oral route due to fecal contamination of water supplies or food; person-to-person transmission is uncommon.
The incubation period following exposure to the hepatitis E virus ranges from three to eight weeks, with a mean of 40 days.Outbreaks of epidemic hepatitis E most commonly occur after heavy rainfalls and monsoons because of their disruption of water supplies. Major outbreaks have occurred in New Delhi, India (30,000 cases in 1955–1956), Burma(20,000 cases in 1976–1977), Kashmir, India (52,000 cases in 1978), Kanpur, India (79,000 cases in 1991), and China (100,000 cases between 1986 and 1988).
DEFRA said that there was evidence that the increase in hepatitis E in the UK was due to food-borne zoonoses, citing a study that found 10% of pork sausages on sale in the UK contained the virus. Some research suggests that food must reach a temperature of 70°C for 20 minutes to eliminate the risk of infection. An investigation by the Animal Health and Veterinary Laboratories Agency found hepatitis E in 49% of pigs in Scotland.
Prevention
Sanitation
Improving sanitation is the most important measure in prevention of hepatitis E; this consists of proper treatment and disposal of human waste, higher standards for public water supplies, improved personal hygiene procedures and sanitary food preparation. Thus, prevention strategies of this disease are similar to those of many others that plague developing nations, and they require large-scale international financing of water supply and water treatment projects.
Vaccines
A vaccine based on recombinant viral proteins was developed in the 1990s and tested in a high-risk population (military personnel of Nepal) in 2001.The vaccine appeared to be effective and safe, but development stopped for economical reasons, since hepatitis E is rare in developed countries.There is no licensed hepatitis E vaccine for use in the US.
Although other HEV vaccine trials, including trials conducted in populations in southern Asia, have shown candidate vaccines to be effective and well-tolerated, these vaccines have not yet been produced or made available to susceptible populations. The exception is China. After more than a year of scrutiny and inspection by China's State Food and Drug Administration (SFDA), a hepatitis E vaccine developed by Chinese scientists was available at the end of 2012. This vaccine—called HEV 239 and sold as Hecolin by its developer Xiamen Innovax Biotech—was approved for prevention of hepatitis E in 2012 by the Chinese Ministry of Science and Technology, following a phase 3 trial on two groups of 50,000 people each from Jiangsu Province where none of the vaccinated became infected during a 12-month period, compared to 15 in the group given placebo treatment.The first vaccine batches came out of Innovax' factory in late October 2012, and will be sold to Chinese distributors.
Treatment
Apart from supportive care, no specific validated treatment exists for acute hepatis E infection. Although ribavarin is not registered for Hepatitis E treatment, there is off-label experience for treating chronic Hepatitis E with this compound. The use of low doses, 600 to 800 milligrams per day, of ribavirin over a three-month period has been associated with viral clearance in about two-thirds of chronic cases.Other possible treatments include peginterferon or a combination of ribavirin and peginterferon. In general chronic HEV infection is associated with immunosuppressive therapies, but remarkably little is known about how different immunosuppressants affect HEV infection. In one thirds of patients with solid-organ transplantation viral clearance can be achieved by temporal reduction of the level of immunosuppression.Calcineurin inhibitors (like cyclosporin) stimulate and mycophenolic acid inhibit replication of Hepatitis E Virus and this should be considered when physicians select immunosuppressive therapies for patients at risk for Hepatitis E, for instance recipients of organ transplants.
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%.How Is Typhoid Fever Diagnosed?
After the ingestion of contaminated food or water, the Salmonella bacteria invade the small intestine and enter the bloodstream temporarily. The bacteria are carried by white blood cells in the liver, spleen, and bone marrow, where they multiply and renter the bloodstream. People develop symptoms, including fever, at this point. Bacteria invade the gallbladder, biliary system, and the lymphatic tissue of the bowel. Here, they multiply in high numbers. The bacteria pass into the intestinal tract and can be identified in stool samples. If a test result isn't clear, blood samples will be taken to make a diagnosis.
What Are the Symptoms of Typhoid Fever?
The incubation period is usually 1-2 weeks, and the duration of the illness is about 3-4 weeks. Symptoms include:
Treatments
1. Take Temperature
No treatment is necessary for a mild fever unless the person is uncomfortable. If the fever is 102º or higher:
Seek medical help immediately if the person has:
Contact a doctor if the high body temperature lasts for more than three days or gets worse.
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 severe 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.
Symptoms of hepatitis A
You can fall ill any time between 15 and 50 days after catching the virus. The average incubation period for the virus is 28 days. Many infected people, particularly children less than five years old, show few or no symptoms.
For older children and adults, the symptoms include:
- fever
- nausea
- abdominal discomfort
- dark urine
- yellow skin and eyes (jaundice).
Complications of hepatitis A
Relapses of hepatitis A occur in around 10 per cent of cases, although people who have relapses fully recover. Hepatitis A does not cause chronic liver disease.
Complications of hepatitis A are rare but the infection can lead to fulminant hepatitis, which is an acute form of hepatitis that can cause liver failure. The risk of death from fulminant hepatitis increases with age.
Causes of hepatitis A
Hepatitis A is caused by a virus. The virus can survive for several hours outside the body but persists on the hands and in food for even longer and is resistant to heating and freezing.
The virus is spread when it enters the mouth, which can happen when hands, foods or other items are contaminated with the faeces of a person with hepatitis A. The disease can also be spread sexually by oral–anal contact. A person with hepatitis A is infectious from two weeks before they show symptoms to one week after they become jaundiced.
Reducing the risk of hepatitis A
Practising strict personal hygiene is essential to reducing the risk of hepatitis A. Steps you can take include:
- Wash your hands with soap and hot running water before handling food, after going to the toilet and after handling used condoms or having contact with nappies or the anal area of another person.
- Clean bathrooms and toilets often, paying attention to toilet seats, handles, taps and nappy change tables.
- Boil your drinking water if it comes from an untreated source, such as a river.
Careful selection and preparation of food and drink is vital and suggestions include:
- Leave it alone if you cannot peel it or boil it.
- Don’t eat uncooked foods, particularly vegetables and fruit that cannot be peeled before eating, shellfish or unpackaged drinks or ice.
Tests used to diagnose hepatitis A may include:
- medical history – plus immunisation status and travel history
- physical examination
- blood test – a sample of your blood will be sent to a laboratory to confirm the diagnosis.
There is no specific treatment for hepatitis A. In most cases, your immune system will clear the infection and your liver will completely heal. Treatment aims to ease symptoms and reduce the risk of complications. Options may include:
- Rest – hepatitis A can make you tired and you have less energy for day-to-day life, so you should rest when necessary.
- Eat small meals more often – nausea can affect your ability to eat and can contribute to tiredness so eat high-calorie foods if nausea is a problem.
- Protect your liver – the liver processes medications and alcohol so avoid alcohol and review your medications with your doctor.
Signs and symptoms
Acute infection
The incubation period of hepatitis E varies from 3 to 8 weeks. After a short prodromal phase symptoms lasting from days to weeks follow. They may include jaundice, fatigue and nausea. The symptomatic phase coincides with elevated hepatic aminotransferase levels.
Viral RNA becomes detectable in stool and blood serum during incubation period. Serum IgM and IgG antibodies against HEV appear just before onset of clinical symptoms. Recovery leads to virus clearance from the blood, while the virus may persist in stool for much longer. Recovery is also marked by disappearance of IgM antibodies and increase of levels of IgG antibodies.
Chronic infection
While usually an acute disease, in immunocompromised subjects—particularly in solid organ transplanted patients—hepatitis E may cause a chronic infection.Occasionally this may cause liver fibrosis and cirrhosis.
Transmission
Hepatitis E is prevalent in most developing countries, and common in any country with a hot climate. It is widespread in Southeast Asia, northern and central Africa, India, and Central America. It is spread mainly by the fecal-oral route due to fecal contamination of water supplies or food; person-to-person transmission is uncommon.
The incubation period following exposure to the hepatitis E virus ranges from three to eight weeks, with a mean of 40 days.Outbreaks of epidemic hepatitis E most commonly occur after heavy rainfalls and monsoons because of their disruption of water supplies. Major outbreaks have occurred in New Delhi, India (30,000 cases in 1955–1956), Burma(20,000 cases in 1976–1977), Kashmir, India (52,000 cases in 1978), Kanpur, India (79,000 cases in 1991), and China (100,000 cases between 1986 and 1988).
DEFRA said that there was evidence that the increase in hepatitis E in the UK was due to food-borne zoonoses, citing a study that found 10% of pork sausages on sale in the UK contained the virus. Some research suggests that food must reach a temperature of 70°C for 20 minutes to eliminate the risk of infection. An investigation by the Animal Health and Veterinary Laboratories Agency found hepatitis E in 49% of pigs in Scotland.
Prevention
Sanitation
Improving sanitation is the most important measure in prevention of hepatitis E; this consists of proper treatment and disposal of human waste, higher standards for public water supplies, improved personal hygiene procedures and sanitary food preparation. Thus, prevention strategies of this disease are similar to those of many others that plague developing nations, and they require large-scale international financing of water supply and water treatment projects.
Vaccines
A vaccine based on recombinant viral proteins was developed in the 1990s and tested in a high-risk population (military personnel of Nepal) in 2001.The vaccine appeared to be effective and safe, but development stopped for economical reasons, since hepatitis E is rare in developed countries.There is no licensed hepatitis E vaccine for use in the US.
Although other HEV vaccine trials, including trials conducted in populations in southern Asia, have shown candidate vaccines to be effective and well-tolerated, these vaccines have not yet been produced or made available to susceptible populations. The exception is China. After more than a year of scrutiny and inspection by China's State Food and Drug Administration (SFDA), a hepatitis E vaccine developed by Chinese scientists was available at the end of 2012. This vaccine—called HEV 239 and sold as Hecolin by its developer Xiamen Innovax Biotech—was approved for prevention of hepatitis E in 2012 by the Chinese Ministry of Science and Technology, following a phase 3 trial on two groups of 50,000 people each from Jiangsu Province where none of the vaccinated became infected during a 12-month period, compared to 15 in the group given placebo treatment.The first vaccine batches came out of Innovax' factory in late October 2012, and will be sold to Chinese distributors.
Treatment
Apart from supportive care, no specific validated treatment exists for acute hepatis E infection. Although ribavarin is not registered for Hepatitis E treatment, there is off-label experience for treating chronic Hepatitis E with this compound. The use of low doses, 600 to 800 milligrams per day, of ribavirin over a three-month period has been associated with viral clearance in about two-thirds of chronic cases.Other possible treatments include peginterferon or a combination of ribavirin and peginterferon. In general chronic HEV infection is associated with immunosuppressive therapies, but remarkably little is known about how different immunosuppressants affect HEV infection. In one thirds of patients with solid-organ transplantation viral clearance can be achieved by temporal reduction of the level of immunosuppression.Calcineurin inhibitors (like cyclosporin) stimulate and mycophenolic acid inhibit replication of Hepatitis E Virus and this should be considered when physicians select immunosuppressive therapies for patients at risk for Hepatitis E, for instance recipients of organ transplants.
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%.How Is Typhoid Fever Diagnosed?
After the ingestion of contaminated food or water, the Salmonella bacteria invade the small intestine and enter the bloodstream temporarily. The bacteria are carried by white blood cells in the liver, spleen, and bone marrow, where they multiply and renter the bloodstream. People develop symptoms, including fever, at this point. Bacteria invade the gallbladder, biliary system, and the lymphatic tissue of the bowel. Here, they multiply in high numbers. The bacteria pass into the intestinal tract and can be identified in stool samples. If a test result isn't clear, blood samples will be taken to make a diagnosis.
What Are the Symptoms of Typhoid Fever?
The incubation period is usually 1-2 weeks, and the duration of the illness is about 3-4 weeks. Symptoms include:
- Poor appetite
- Headaches
- Generalized aches and pains
- Fever as high as 104 degrees Farenheit
- Lethargy
- Diarrhea
Treatments
1. Take Temperature
- Temperature can be taken orally, rectally, or under the armpit.
- A person is considered feverish if oral temperature is above 100º F (37.8 C) or rectal temperature is above 100.7º F (38.2 C). Temperatures measured under the armpit are not considered as accurate and can be as much as 1º F lower than an oral measurement.
- A temperature below 100.4º (38 C) is considered a low-grade or mild fever. It means that the body is responding to an infection.
No treatment is necessary for a mild fever unless the person is uncomfortable. If the fever is 102º or higher:
- Give an over-the-counter medicine such as acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) as directed on the label. Warning: Do NOT give aspirin to anyone age 18 or younger unless directed to do so by a doctor.
- Bathing or sponging in lukewarm water may bring the temperature down. Do not use cold water or alcohol.
- Have the person wear light clothing and use a light cover or sheet -- overdressing can make body temperature go up. If the person gets chills, use an extra blanket until they go away.
- Have the person drink plenty of fluids to stay hydrated.
Seek medical help immediately if the person has:
- A history of serious illness such as AIDS, heart disease, cancer, or diabetes, or if the person is taking immunosuppressant drugs
- A high fever that doesn't respond to fever-reducing medicine
- Been exposed to extremely hot weather and feels hot but is not sweating
- A stiff neck, is confused, or has trouble staying awake
- Severe pain in the lower abdomen
- Severe stomach pain, vomits repeatedly, or has severe diarrhea
- Skin rashes, blisters, or a red streak on an arm or leg
- A severe sore throat, severe swelling of the throat, or a persistent earache
- Pain with urination, back pain, or shaking chills.
- A severe cough, coughs up blood, or has trouble breathing
Contact a doctor if the high body temperature lasts for more than three days or gets worse.
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 severe 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.