Human Immunodeficiency Virus (HIV) is the virus that causes Acquired Immune Deficiency Syndrome (AIDS.) HIV affects a person’s immune system, the body’s natural defense against disease. The only way to become infected with HIV is through contact with blood or other body fluids like semen or vaginal fluid from someone who has the HIV virus. HIV is usually transmitted through unprotected sex or by using needles or syringes used by someone with HIV. It can also be passed from an infected pregnant mother to her fetus. There is no cure for HIV. When left untreated, HIV can turn into AIDS. With proper treatment, people diagnosed with AIDS can maintain a relatively healthy life. But without treatment, AIDS is fatal.
Amebiasis is a gastrointestinal disease caused by a parasite called Entamoeba histolytica. While anyone can be diagnosed with amebiasis, it is much more common in developing countries that have poor sanitary conditions. In the United States, it is most often found in people who immigrated from or recently visited a developing country, or those who live in institutional settings with poor sanitary conditions. You can become infected with the E. histolytica parasite by putting something in your mouth that was contaminated with the stool of someone infected with it, by consuming food or water that was contaminated with it, or by touching surfaces contaminated with it and then touching your mouth. On average, about one in 10 people who are infected with E. histolytica becomes sick from the infection. The symptoms are generally mild and can include loose stools, stomach pain, and stomach cramping. It can, however, lead to amebic dysentery, a severe form of amebiasis associated with stomach pain, bloody stools, and fever. While not common, E. histolytica can invade the liver and form an abscess or spread to other parts of the body, such as the lungs or brain. In rare cases, it can be fatal. Amebiasis is treated with antibiotics.
Anthrax is a disease caused by bacteria called Bacillus anthracis. This bacteria can form spores, which contain the vital parts of the bacteria. The bacteria spores can live in soil for many years. Anthrax is not contagious, meaning you can’t “catch” it from someone who is sick with anthrax. Anthrax most commonly occurs in grazing animals such as cattle, sheep, and goats that get the disease from eating spores in the soil. When the animal dies and is not disposed of properly, new spores can be left behind in the soil. Anthrax is not spread through animal milk or from one animal to another. Human cases of anthrax are mostly seen in poor countries where people may get sick from preparing and eating food from an animal that died of anthrax. It is also seen in people who handle animal hides and skins, such as wool factory workers. Anthrax has also been made into a biological weapon.
Babesiosis is an infection of red blood cells by a parasite called Babesia. It is transmitted through a tick bite. Symptoms include fever, chills, muscle pain, and fatigue. Nearly all of cases of babesiosis have been in the northeastern United States and have been caused by a type of Babesia called Babesia microti. Six cases of babesiosis have occurred in California since 1993. These were caused by a different kind of Babesia called Babesia duncani.
Botulism is a rare but serious disease caused by a nerve toxin that is produced by the bacterium Clostridium botulinum. It can cause the body to become paralyzed. There are three main kinds of botulism: food-borne botulism is caused by eating foods that contain the botulism toxin; wound botulism is caused by toxin produced in a wound infected with Clostridium botulinum; and infant botulism is caused by consuming the spores of the botulinum bacteria, which then grow in the intestines and release toxin. All forms of botulism can be fatal and are considered medical emergencies.
Brucellosis is an infection caused by Brucella bacteria. There are several types of Brucella and each type is commonly associated with a specific animal host. For example, Brucella abortus is associated with cattle, Brucella melitensis with sheep and goats, Brucella canis with dogs, and Brucella suis with pigs. The most common way to get brucellosis is by consuming unpasteurized dairy products and through contact with livestock. Illness generally occurs one to three months after being exposed to the bacteria, but can take several months. Symptoms are nonspecific and include fever, sweats, malaise, headache, and back pain. A recurring fever and arthritis can occur if patients go untreated for long periods. Infections that last for more than 12 months can result in infections in the bones, joints, liver, kidney, spleen, or heart valves. Brucellosis is treated with antibiotics over a prolonged period of time.
Campylobacteriosis is a gastrointestinal disease caused by a type of bacteria called Campylobacter. Illness usually occurs two to five days after exposure to the bacteria and lasts about a week. Symptoms are generally mild and include diarrhea, abdominal cramps, and fever. A small number of people may experience joint pain and swelling even after the infection is gone. Campylobacteriosis can be serious and even life-threatening for people with compromised immune systems. In addition, a rare disease called Guillain-Barre syndrome, which causes weakness and paralysis, can occur several weeks after the initial illness. Campylobacteriosis is most commonly associated with eating raw or undercooked poultry, or foods that have come in contact with raw or undercooked poultry. Campylobacteriosis can also result from drinking water that has been contaminated by infected birds or cows, contact with infected dogs and cats, and from drinking or eating products made with unpasteurized milk from infected cows. Campylobacteriosis is treated with antibiotics, however most people recover fully without any antibiotics.
Chickenpox (also called varicella) is a common childhood disease that is caused by a virus. It is usually mild, but it can be serious, especially in young infants and adults. The chickenpox virus can be spread from person to person through the air or by contact with fluid from chickenpox blisters. It can lead to severe skin infection, scars, pneumonia, brain damage, or death. Two doses of chickenpox vaccine are recommended for people who have not had disease. Children should receive the first dose of vaccine at age 12 to 15 months or at any age after that if they have never had chickenpox. School-aged children should receive the second dose at age 4 to 6 years. People who do not get the vaccine until age 13 or older should get two doses, four to eight weeks apart.
Chlamydia is a common sexually transmitted infection caused by Chlamydia trachomatis bacteria. Often the infection does not cause any symptoms. But if it goes untreated, it can cause serious reproductive health problems such as pelvic inflammatory disease (PID) and infertility. Chlamydia can also cause infections in newborn babies. Chlamydia can be diagnosed with a simple test and treated with antibiotics.
Cryptosporidisis is a gastrointestinal infection caused by a tiny parasite. It is transmitted through feces or feces-contaminated water. Symptoms of cryptosporidiosis generally begin two to 10 days after becoming infected with the parasite and last one to two weeks. The most common symptom is watery diarrhea. Other symptoms include stomach cramps or pain, dehydration, nausea, vomiting, fever, and weight loss. Occasionally, people may experience a recurrence of symptoms after a brief period of recovery before the illness ends. Symptoms can come and go for up to 30 days. People with weakened immune systems, including those with AIDS, may develop serious, chronic, and sometimes fatal illness.
Diphtheria is caused by bacteria and usually affects the tonsils, throat, nose or skin. It is passed from person to person through the air, usually by breathing in diphtheria bacteria after an infected person has coughed, sneezed, or laughed. Diphtheria can lead to breathing problems, heart failure, paralysis, and sometimes death. The DTaP, Td, and Tdap vaccines all protect against diphtheria. Children need four doses of DTaP by age 15 months and a Tdap booster at age 11 or 12. Adults need a tetanus/diphtheria (Td) booster every 10 years after the primary series has been completed.