Infectious Diseases and Contagious
Infectious diseases are caused by pathogenic microorganisms, such as bacteria, viruses, parasites or fungi. These diseases can spread in the environment or be transmitted from person to person, causing the disease to reside in our communities.
Find information about…
Resources on blood borne infections: Viruses that are carried by the blood, especially hepatitis B, hepatitis C and HIV.
Enteric and foodborne illness
Enteric Disease Resources: Intestinal illnesses caused by microorganisms such as viruses, bacteria and parasites.
Respiratory disease resources: infections of the respiratory system caused by organisms such as viruses or bacteria.
Sexually transmitted infections (STIs)
Resources on STIs: infections caused by microorganisms such as viruses or bacteria transmitted through sexual contact.
Diseases preventable by vaccination
Resources on the prevention and control of vaccine-preventable diseases.
Zoonotic and vector-borne diseases
Resources on vector-borne and zoonotic diseases: viruses, bacteria or parasites transmitted to humans by animals or insects.
Blood-borne Infectious diseases
Blood-borne infections (gs-STIs) are viruses that are carried by the blood, particularly hepatitis B, hepatitis C and the human immunodeficiency virus (HIV). They can be transmitted through sexual contact, by sharing needles, in needlestick injuries, from mother to child during pregnancy, during childbirth or while breastfeeding. STIs can also be found in other body fluids. We provide public health workers with the expertise, support and resources to prevent and control g-STIs.
- Hepatitis B (acute)
- Hepatitis B (chronic)
- Hepatitis C
- HIV / AIDS
Hepatitis B (acute)
Acute hepatitis B is an infection that attacks the liver. It is caused by the hepatitis B virus and is spread through contact with the blood or other body fluid of an infected person, including during sex or needle exchange, or from mother to mother. child at birth. Acute infection presents within six months of exposure to the virus. Some people are mildly ill and have few or no symptoms, but in others the illness is serious and results in hospitalization or death. Most healthy adults clear the virus without treatment. Chronic hepatitis B sets in if the acute infection lasts longer than six months. Hepatitis B can be prevented by vaccination, which is available to grade 7 students and those at high risk of infection.
Hepatitis B (chronic)
Hepatitis B is an infection that attacks the liver. It is caused by the hepatitis B virus and is spread through contact with the blood or other body fluid of an infected person, including during sex or needle exchange, or from mother to mother. child at birth. Chronic infection sets in if the immune system cannot clear the virus and it stays in the blood and liver for more than six months. Possible long-term complications of chronic infection include cirrhosis and liver cancer. In some cases, an antiviral medication is recommended to prevent complications of the infection. Hepatitis B can be prevented by vaccination, which is available to grade 7 students and those at high risk of infection.
Hepatitis C infection is caused by a virus that attacks the liver. It is mainly spread through contact with the blood of an infected person, including through the exchange of needles or other medical equipment, and from mother to child during childbirth. Hepatitis C can cause acute and chronic infections, often asymptomatic. Chronic infections can lead to serious liver disease or cancer. As of yet, there is no vaccine for hepatitis C, but effective treatments are available.
Human immunodeficiency virus (HIV)
Infection with HIV attacks the immune system and destroys cells that fight other infections or diseases. AIDS is the major form of HIV infection. The virus is most commonly spread through unprotected sexual activity and the multiple use of contaminated needles or syringes. There is no cure for HIV / AIDS, but treatments can effectively control the syndrome.
Enteric and foodborne infectious diseases
Enteric disease is caused by microorganisms such as viruses, bacteria, and parasites that cause intestinal disease. These illnesses are most often caused by consuming contaminated food or water, and some can be passed from person to person. It is estimated that only a small proportion of enteric and foodborne illnesses are actually reported to public health. We provide public health workers with the expertise, support and resources to prevent and control enteric disease.
Hepatitis A (Hep A)
Paralyzing shellfish poisoning
Verotoxin producing Escherichia coli (E. coli)
Amebiasis is a disease caused by the parasite Entamoeba histolytica. It is typically linked to travel. Found worldwide, however, it is more common in areas where hygiene is poor. It can be passed from person to person through direct contact, or by consuming contaminated food or water. Symptoms include stomach cramps, watery or bloody diarrhea, and weight loss.
A rare but serious disease, botulism is caused by a toxin produced by the bacteria Clostridium botulinum. This disease can occur after ingestion of food contaminated with the toxin, infection of an open wound, or – especially in babies – ingestion of spores that produce toxins in the intestines. Botulism is treated with a medicine that neutralizes the toxin.
Campylobacteriosis is a common bacterial disease that causes bowel problems such as diarrhea, abdominal pain, nausea, and vomiting. Infection occurs from direct contact with animals or from the ingestion of undercooked red or white meats, unpasteurized dairy products or contaminated water. Most cases are mild, but the infection can cause serious complications in very young, elderly or immunocompromised patients.
Cholera is a bacterial disease caused by eating food or water contaminated with the bacteria Vibrio choleae. This disease, is usually contracted in countries with poor sanitation. Symptoms, of moderate to acute intensity, include profuse watery diarrhea, nausea and vomiting. The loss of fluids causes rapid dehydration and requires urgent treatment.
Creutzfeldt-Jakob disease (CJD) is a degeneration of the central nervous system that results in death. It is caused by the development of prions, an abnormal form of a protein that can transmit the disease. CJD may occurs sporadically, either through inherited genetic mutations or through contact with a medical device that had been used on an infected patient and was subsequently improperly reprocessed. A variant of CJD is associated with the ingestion of contaminated beef.
Cryptosporidiosis is an intestinal disease caused by the Cryptosporidium parasite. Symptoms include nausea, abdominal pain, and diarrhea. Infection usually occurs through consumption of water or food contaminated with infected feces, for example, by swallowing water from a swimming pool, lake or river. The infection can also spread from person to person. There is no specific treatment, other than rehydration, when recommended.
Cyclosporosis is an intestinal disease caused by the parasite Cyclospora cayetanesis, found in countries with tropical or subtropical climates. The cases listed in the province are linked either to travel or to the importation of food. Previous outbreaks have been associated with imported products and plants. The illness, which causes diarrhea, can be treated with antibiotics.
Giardiasis is an enteric disease caused by ingestion of the parasite Giardia, usually by consuming contaminated food or water. The disease can also be passed from person to person, especially in child care settings. Symptoms of the infection include diarrhea, gas, stomach pain, nausea and vomiting. Giardiasis can be prevented by washing your hands thoroughly and avoiding drinking untreated water.
Hepatitis A is an acute infection of the liver caused by a virus. Infection occurs by swallowing food or water contaminated with infected feces and can easily be passed from person to person. In most young children, the disease does not have any symptoms or it has not been detected. In adults, for the most part, symptoms include fatigue, abdominal pain, nausea, and jaundice. Hepatitis A is often associated with travel to areas where the disease is more common. There is a vaccine for its prevention.
Listeriosis is an intestinal infection caused by the bacteria Listeria monocytogenes. It is spread by ingesting contaminated foods such as ready-to-eat meats, soft cheeses, milk and raw vegetables. Seniors, pregnant women, and people with immunodeficiency are the most prone to complications and should avoid high-risk foods.
Paralyzing shellfish poisoning
Paralyzing shellfish poisoning is caused by ingesting a toxin found in mussels, oysters or clams harvested from water where the toxin is present. Symptoms usually appear 30 minutes to 3 hours after eating contaminated food. Symptoms include tingling, numbness, paralysis, nausea and vomiting. People can reduce the risk of poisoning by purchasing shellfish only from safe sources.
Paratyphoid fever is caused by the bacteria Salmonella enterica Paratyphi. Symptoms vary and include fever, headache, loss of appetite, and abdominal pain. The disease is spread by eating contaminated food or water and can be spread from person to person. It is associated with travel to South Asia and other developing countries. Good hygiene and good food preparation can help prevent this condition.
Salmonellosis is caused by bacteria of the genus Salmonella. It is mainly spread by swallowing food or water contaminated with feces or by contact with infected people. Diarrhea is a common symptom, in addition to abdominal cramps and fever. Salmonellosis can be prevented by carefully cooking meats and eggs, avoiding unpasteurized milk, and practicing good hand hygiene, especially after handling raw meat, uncooked eggs, or live animals.
Shigellosis is an infection caused by the Shigella bacteria. Infection can occur after ingestion of food, drink or recreational water that is contaminated with feces, through sexual contact with an infected person, and through contact with contaminated surfaces. Only a small number of bacteria are needed to make people sick. Symptoms include diarrhea, stomach pain and fever. Young children, travelers to developing countries, and men who have sex with other men are at higher risk of getting shigellosis.
Trichinellosis is a foodborne infection caused by an intestinal parasite belonging to the Trichinella family. Infection can occur from eating contaminated raw or undercooked meat. Symptoms include nausea, diarrhea, and vomiting. Other symptoms appear as the disease progresses, including headache, muscle pain, fever, and swelling of the face. Infection can be prevented by cooking the meat sufficiently.
Coronavirus disease 2019 (COVID-19)
Variants are viruses that have changed or mutated.
All viruses evolve and can produce variants. While in most cases the properties of the virus change little and the mutation has little effect on the population, in other cases there may be a greater impact.
Coronaviruses often produce variants, but these only become of concern when the changes have significant public health or clinical practice implications for at least one of the following:
- virulence (severity of the disease);
- vaccine efficacy;
- diagnostic tests.
Enterovirus D68 (EV-D68) causes acute respiratory problems. Symptoms range from a mild cold-like condition, with coughing and wheezing, to serious infections requiring hospitalization. Enterovirus infections are more common in late summer and fall, with some variation from year to year.
Neonatal group B streptococcal infection (GAB)
Diseases associated with neonatal group B streptococcal infection are caused by the group B Streptococcus bacteria (also called Streptococcus agalactiae). This bacteria is sometimes found in the genital tract of a healthy woman and can be passed to the baby during childbirth. It can cause sepsis (blood poisoning), pneumonia, and sometimes meningitis in newborns.
Invasive group A streptococcus (GAS)
Invasive group A streptococcus (GAS) infection is caused by the transmission of the bacteria from person to person through direct contact with secretions from the nose, throat or from a wound or droplets of saliva. Some people get the bacteria in the throat or on the skin, without showing symptoms or if they are only mildly ill. In rare cases, the bacteria become ‘invasive’, or GAS, and enter the bloodstream or deep into tissue. The disease then takes a serious form which can be life threatening.
The flu or Influenza is a respiratory virus that circulates, most commonly in the fall and winter (for seasons countries). It is spread from person to person by coughing, sneezing, or by close contact with an infected person. It can cause mild to severe breathing problems. Although anyone can get it, very young children, the elderly and people with certain conditions are more prone to complications. The best way to prevent infection is to get the seasonal influenza vaccine every year.
Legionellosis (Legionella, Legionnaire’s disease)
Legionella is a bacterium that is found in natural aquatic environments and can enter domestic water systems, such as plumbing, air conditioners, whirlpool tubs, showers and decorative fountains. Inhalation of droplets or vapor of contaminated water can cause mild infections (Pontiac fever), accompanied by flu-like symptoms, or pneumonia (Legionnaires’ disease). Seniors and people with immunodeficiency are at greater risk of contracting the disease.
Leprosy (Hansen’s disease)
Leprosy is a bacterial infection caused by Mycobacterium leprae. To date, only a very small number of imported cases have been recorded each year. Although its mode of spread remains partly misunderstood, it appears to be based on close and frequent contact with untreated infected people. Leprosy, which attacks the skin, nerves and mucous membranes, is treated with antibiotics. Untreated cases can lead to serious nerve damage, including paralysis of the hands and feet.
Middle East Respiratory Syndrome Coronavirus (MERS-CoV)
The Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is a coronavirus, a family of viruses that can cause a range of respiratory illnesses from mild to severe. MERS-CoV is usually transmitted from camels to humans. Person-to-person transmission only occurs through close contact, usually in a hospital setting. Most of the cases have been reported in countries in the Middle East, largely in Saudi Arabia. There is currently no vaccine or specific treatment for this virus.
Tuberculosis is a respiratory disease caused by the bacteria Mycobacterium tuberculosis. Tuberculosis can be spread when a person with active disease in their lungs or airways coughs, sneezes or talks. Exposure to TB can also lead to latent TB infection – people with TB have no symptoms and cannot pass TB to other people. Tuberculosis is a disease that can be treated and cured with antibiotics and can be prevented.
Sexually transmitted infections (STIs)
Sexually transmitted infections are caused by microorganisms such as viruses or bacteria that are transmitted through sexual contact, especially during vaginal, oral or anal sex. According to the World Health Organization, there are about 350 million new cases worldwide every year.
A sexually transmitted venereal disease caused by the spirochete bacterium Treponema pallidum. The main route of transmission is through sexual contact; this infection can also be passed from mother to fetus during pregnancy or at birth, causing congenital syphilis. Other human diseases caused by Treponema pallidum include yaws or patek (subspecies pertenue), pinta (subspecies carateum) and bejel (subspecies endemicum). Read also: Syphilis | Signs and symptoms: Primary, Secondary, Latent, Tertiary, Congenital
Gonorrhea Gonorrhea (Gonorrhea) – discharge of pus from the penis
Gonorrhea is a sexually transmitted disease caused by the bacterium Neisseria gonorrhoeae. Some men who get gonorrhea do not show any complaints or symptoms. But some others can show symptoms in the form of pus coming out of the penis accompanied by pain or burning when urinating
Sexually transmitted diseases that can occur in both men and women. Also known as gonorrhea or gonorrhea.
HIV infection and AIDS
It compromises your immune system by destroying infection-fighting white blood cells. AIDS stands for acquired immunodeficiency syndrome. This is the final stage of HIV infection. Not everyone with HIV can develop AIDS.
HIV is most commonly spread through unprotected sex with an infected person. It can also be spread by sharing needles or through contact with the blood of an infected person. Pregnant women can give it to their babies during pregnancy or childbirth.
Chlamydia is a common sexually transmitted venereal disease. It is caused by a bacterium called Chlamydia trachomatis. It can infect both men and women. Women can get chlamydia in the cervix, rectum or throat. Men can get chlamydia in the urethra (inside the penis), rectum or throat.
You can get or catch chlamydia when you have oral, vaginal or anal sex with someone who has the infection. A woman can also give birth to chlamydia in her baby during childbirth.
If you have had chlamydia and were treated in the past, you can become infected again if you have unprotected sex with someone who has it.
Most people with genital herpes do not know they have the disease, so the diagnostic rate significantly underestimates its occurrence. This disease can be transmitted through direct contact, sexual intercourse, oral sex or from mother to baby.
Genital herpes is a sexually transmitted infection (STI) caused by the herpes simplex virus (HSV). This can cause venereal sores in the genital area or rectum, buttocks and thighs. You can get it from vaginal, anal or oral sex with someone who has it. The virus can spread even if the wound is not present. Mothers can also infect their babies during delivery.
You usually get sores near the area where the virus entered the body. Sores are blisters on the skin that break and become painful, and then heal.
Trichomoniasis (Trichomonas vaginalis)
Trichomoniasis is a sexually transmitted venereal disease caused by a parasite. You get it through sexual intercourse with an infected partner. Many people do not have any symptoms. If you develop symptoms, they usually occur within 5 to 28 days of being infected.
Human papillomaviruses (HPV)
Is a group of viruses. They can cause warts on various parts of your body. There are more than 200 types. About 40 of these types affect the genitals.
HPV is spread through sexual contact with an infected partner. Some of them can put you at risk for cancer.
Hepatitis B and C
Hepatitis B virus
Transmission is not as easy as the hepatitis A virus. The hepatitis B virus is transmitted through blood or blood products. Transmission usually occurs between drug users who share needles, or between sexual partners (both heterosexual and homosexual men).
Pregnant women who are infected with hepatitis B can transmit the virus to their babies during childbirth. Hepatitis B can be transmitted by healthy people who carry the hepatitis B virus.
In the Far East and Africa, some cases of hepatitis B progress to chronic hepatitis, cirrhosis and liver cancer.
Hepatitis C virus
Causes at least 80% of hepatitis cases blood transfusion. Hepatitis C virus is most often transmitted through drug users who share needles. Sexual transmission is rare. For reasons that remain unclear, people with “alcoholic liver disease” often develop hepatitis C.
The main method of transmission in developed countries is through injection drug use. In developing countries the main methods of transmission are through blood transfusions and unsafe medical procedures and having sex without a latex condom.
Synchroid or chancroid is a sexually transmitted venereal disease characterized by pain in the genitals.
Chancroid is known to spread from one person to another through sexual contact.
Chancroid is a bacterial infection caused by Haemophilus ducreyi. This disease is mainly found in developing countries, in association with commercial sex workers and their clients.
Pubic lice (pubic lice) and scabies (scabies)
Pubic lice (pubic lice)
Pubic lice are a form of lice that live in hair in the genital area and sometimes on other areas of the body with coarse hair, such as the armpits or eyebrows.
Pubic lice (Pthirus pubis) are tiny parasitic insects that can infest hairy areas of the human body, generally pubic hair. This parasite lives by sucking blood through the skin, and can cause itching in the infected area.
They are usually spread by sexual contact, although they can also occasionally be transmitted by infected bed linen and clothing.
Symptoms include itching in the genital area and visible lice or eggs.
You should know that pubic lice are not the same as head lice and almost never infect hair on the head.
Ureaplasma urealyticum infection is a sexual health problem since it is an infection that can be transmitted through the genitals or through oral-genital contact. It can cause complications in women and sometimes serious in newborns. That is why it is important to prevent and treat it.
The bacteria Ureaplasma urealyticum is a member of the mycoplasma family. Mycoplasmas can cause infections that can affect different organs. They affect both humans and animals. Found in the genital tract, the bacterium Ureaplasma urealyticum is said to be commensal, which means that it is the usual host of an organism without causing damage to it. In small quantities, it does not represent any danger.
Diseases preventable by vaccination
Immunization is widely recognized as one of the 20th century’s greatest public health achievements. Vaccines prevent disease (VPD), save lives and reduce health care costs. Immunization programs are an important foundation of the health system.
Haemophilus influenza, of all types
Invasive meningococcal disease
Invasive streptococcal pneumonia
Rubella and congenital rubella syndrome
Zoonotic and vector-borne diseases (any living agent that carries and transmits an infectious pathogen to another living organism; agents regarded as vectors are organisms, such as parasites or microbes)
Zoonotic and vector-borne diseases are caused by a virus, bacteria or parasites and are transmitted to humans by animals or insects. Some animal diseases must be transmitted through a vector (eg, a mosquito or tick) to infect humans.
Public health workers with the expertises are very important, support and resources to prevent and control zoonotic and vector-borne diseases.
Hantavirus pulmonary syndrome
Seoul virus infection
Viral hemorrhagic fevers
West Nile virus
Anthrax is an infectious disease of bacterial origin caused by Bacillus anthracis. The bacteria, which are found naturally in the soil, can infect livestock such as cattle, sheep and pigs. Although the scenario is uncommon, a person can contract anthrax from contact with an infected animal or by ingesting contaminated food of animal origin. Coal is also a potential agent of bioterrorism.
Brucellosis (Malta fever)
Brucellosis is a disease caused by various species of the Brucella bacteria. It can attack livestock. Brucellosis can be spread to people who have consumed unpasteurized or raw dairy products or who have come into contact with infected animals. Personnel who work with livestock are at greater risk of contamination. Symptoms include fever, sweating, fatigue, and headache.
Hantavirus pulmonary syndrome
Hantavirus pulmonary syndrome is caused by a virus found in certain rodents, including deer mice. A person can contract the virus through direct or indirect contact with the saliva, urine or feces of an infected rodent. The infection can lead to acute respiratory failure and hypotension.
Lyme disease is an infection spread by the bite of an infected blacklegged tick. The majority of human cases result from exposure in areas where these ticks are known to be present. Early symptoms may include fever, headache, muscle and joint pain, fatigue, and a red, expansive rash. The best prevention is to avoid tick bites with insect repellent, wearing appropriate clothing, removing ticks as soon as possible after their bites, and destroying tick colonies around the home.
Malaria is a parasitic infection transmitted to humans by the bite of an infected mosquito. Symptoms include fever, headache, chills, and diarrhea. Malaria is not endemic and the reported cases are associated with immigration or recent travel. Visitors to areas where the disease is endemic, such as Africa, South Asia, and Central and South America, are most at risk of becoming infected.
Plague is a disease caused by the bacteria Yersinia pestis. It can be transmitted to humans by fleas that have bitten an infected animal. Plague can also be spread through direct contact with an infected animal or its fluids, or through contact with someone with pneumonic plague. Those infected are likely to have contracted it while traveling abroad. Symptoms include fever, headache, chills, and abdominal pain. Antibiotics are used to treat plague.
Psittacosis (Parrot disease, ornithosis)
Psittacosis is caused by the bacteria Chlamydophila psittaci. It is also known as parrot disease or ornithosis. It is spread to humans through infected birds. Birds of the parrot family are the most common carriers; the least common are poultry, pigeons and seabirds. Although the disease is rare, people who own pet birds or who work with birds (eg, in pet stores, veterinary clinics, farms) are most at risk. Symptoms include fever, headache, rash, muscle pain, and difficulty breathing.
Q fever is an infectious disease caused by the bacteria Coxiella burnetii, which is found in sheep, cattle, goats, cats and dogs. It is transmitted to humans by inhalation of dust contaminated with urine, milk, feces and other fluids of infected animals, or by direct contact with these contaminated elements. Symptoms include fever, chills, headache, weakness, and muscle pain.
Rabies is a viral infection that causes inflammation of the brain and spinal cord and is almost always fatal. Rabies is usually transmitted to humans through the bite of an infected animal. Bats, skunks, foxes and raccoons are the animals most often infected. However, cases of human rabies are very rare. After exposure to a potentially rabid animal, people should wash the wound with plenty of water and seek immediate medical attention to assess whether a post-exposure vaccine is necessary.
Seoul virus infection
Seoul virus is a type of hantavirus transmitted by sewage rats and black rats. Humans can become infected after being exposed to the urine, feces or saliva of infected rats, including contact with litter, or after being bitten. In rare cases, Seoul virus can cause hemorrhagic fever with kidney syndrome which leads to bleeding, shock, and kidney failure.
Tularemia is a rare disease caused by the bacteria Francella tularensis. Wild animals, especially rabbits, and some domestic animals are carriers of this bacteria. The disease is transmitted to humans by the bite of ticks or deer flies, or by handling the carcasses of infected animals. Although tularemia infections can have a number of different clinical patterns, the most common symptoms are an ulcer at the site of infection and swelling of the lymph nodes.
Viral hemorrhagic fevers
Viral hemorrhagic fevers (VHF) include a number of serious and potentially fatal illnesses caused by viruses such as Ebola, Marburg and Lassa. These viruses affect the body’s vascular system and can lead to internal bleeding and organ failure. They are spread primarily through direct contact with infected bodily fluids. Although outbreaks of VHF have occurred in many parts of the world.
West Nile virus
West Nile virus (WNV) is spread by the bite of an infected mosquito. Most people infected with WNV do not have symptoms. Others may have fever, headache and muscle aches, fatigue, rash, meningitis or encephalitis. Exposure to WNV can be prevented by reducing mosquito breeding sites (i.e., standing water) and using personal protection against mosquitoes.
Yellow fever is a mosquito-borne viral infection found in the tropics and subtropics of Africa and Central and South America. The virus is transmitted by the Aedes mosquito species. All reported cases of yellow fever are travel-related, and the fever is not spread between humans. A vaccine can prevent the disease.
Zika virus is a viral infection transmitted by mosquitoes of the genus Aedes aegypti and Aedes albopictus, which also transmit dengue and chikungunya viruses. Zika virus can also be transmitted sexually. Most cases of Zika virus infection are asymptomatic or present with fever, rash and conjunctivitis. However, infection with Zika during pregnancy can lead to a variety of birth complications, including microcephaly, called congenital Zika syndrome.
Information: Cleverly Smart is not a substitute for a doctor. Always consult a doctor to treat your health condition.