Muscovy ducks (Cairina moschata) are a large domesticated duck species that originate from Mexico, Central America, and South America. They are popular as pets and for their meat. However, there has been some concern that Muscovy ducks may carry diseases that can infect humans.
Can Muscovy ducks transmit avian influenza to humans?
Yes, Muscovy ducks can become infected with avian influenza viruses and potentially transmit them to humans. Avian influenza refers to infection with bird flu viruses. There are many different strains of avian influenza virus. Some strains, such as H5N1, have caused outbreaks in poultry and pose a significant threat to human health.
Waterfowl like Muscovy ducks are natural reservoirs for avian influenza viruses. This means the viruses have adapted to infect ducks and geese without causing them harm. The viruses replicate in the duck’s digestive and respiratory tracts and are shed in their saliva, nasal secretions, and feces. The duck then spreads the virus through direct contact with other birds or through contamination of the environment.
Humans can become infected with avian influenza viruses through direct contact with infected birds. This typically requires close contact with respiratory secretions or feces from the duck. Avian influenza does not spread easily from birds to humans. However, some strains like H5N1 and H7N9 have been associated with human cases and even death when transmission occurs. Proper hygiene and cooking of duck meat reduces the risk of transmission.
Major avian influenza outbreaks from Muscovy ducks
- 1999-2000 outbreak in Italy caused by an H7N1 virus
- 2003 outbreak in the Netherlands caused by an H7N7 virus
- 2013 Chinese outbreak of H7N9 traced back to Muscovy ducks
Can Muscovy ducks spread salmonella infections to humans?
Yes, Muscovy ducks can carry and transmit Salmonella bacteria to humans. Salmonella is a common cause of foodborne illness. There are many different types of Salmonella bacteria that can infect birds, some of which are also pathogenic in humans.
Muscovy ducks may have Salmonella bacteria present in their gastrointestinal tract without showing signs of illness. The bacteria are shed in the duck’s feces. Humans can become infected if they ingest anything contaminated with these feces. Common routes of Salmonella transmission from Muscovy ducks include:
- Handling ducklings or adult ducks and then not washing hands before eating
- Consuming undercooked duck eggs
- Eating undercooked duck meat
- Drinking or swimming in water contaminated by duck feces
Infected individuals may develop diarrhea, fever, and abdominal cramps within 12-72 hours after infection. Salmonella can also sometimes spread from the intestines to the bloodstream and cause more serious disease. Proper food handling and cooking practices help prevent Salmonella transmission from Muscovy ducks to humans.
Reported cases of salmonellosis from Muscovy ducks
- 1981 outbreak in Florida affecting 18 people
- 1999 outbreak in Georgia affecting 36 people
- 2012 outbreak in Washington D.C. affecting 51 people
Can humans get botulism from Muscovy ducks?
Yes, it is possible for Muscovy ducks to transmit botulism to humans in rare cases. Botulism is caused by toxins produced by the bacterium Clostridium botulinum. Botulism in ducks occurs when the bacteria grows and produces toxin in decaying vegetation or other material ingested by the ducks.
Ducks show signs of weakness, difficulty standing and holding their heads up, and eventual paralysis or death from the muscle-paralyzing toxins. Humans can develop foodborne botulism if they eat undercooked duck meat containing the botulinum toxins. Infants can get infant botulism by ingesting C. botulinum spores from soil or duck feces, which then produce toxin in the infant’s intestinal tract.
Adult humans can also acquire wound botulism if C. botulinum spores contaminate an open wound and produce toxin within the wound. Direct contact with a duck’s infected feces or soil is the most likely source of contamination. Botulism in humans is rare but life-threatening if not treated immediately with antitoxin.
Cases of botulism potentially linked to Muscovy ducks
- 1981 case of wound botulism in California
- 1999 outbreak of infant botulism in Pennsylvania, 6 cases
- 2009 foodborne botulism outbreak in Argentina, 3 cases
Can Muscovy ducks spread psittacosis to humans?
Psittacosis, also known as parrot fever or ornithosis, is a bacterial disease caused by Chlamydia psittaci. Besides parrots, Chlamydia psittaci can also infect many bird species including ducks, pigeons, turkeys, and chickens.
Muscovy ducks can become infected through inhalation of bacteria spread from the droppings or respiratory secretions of infected birds. Infected ducks may show respiratory signs like nasal discharge, coughing, and eye infections. The bacteria can be shed for months leading to contamination of the environment.
Humans typically get exposed by inhaling or coming into contact with C. psittaci bacteria from infected birds. Flu-like symptoms develop in most patients along with atypical pneumonia. Proper hygiene like wearing gloves and masks when handling ducks reduces infection risk. Antibiotics are effective in treating psittacosis in humans when it is diagnosed early.
Psittacosis outbreaks potentially linked to infected Muscovy ducks
- 1982 outbreak in Louisiana affecting 12 people
- 1995 outbreak in Argentina sickening over 800 poultry plant workers
- 2010 outbreak in Belgium connected to duck eggs, 8 cases
Can you get toxoplasmosis from Muscovy ducks?
Toxoplasmosis is an illness caused by the parasite Toxoplasma gondii. Most mammals and birds can become infected with toxoplasmosis, including Muscovy ducks. Cats are the definitive host where T. gondii reproduces sexually and spreads oocysts in feces.
Ducks can pick up toxoplasmosis by ingesting contaminated soil, water, or feed materials. The parasite forms tissue cysts in the duck’s muscles and other organs. Humans may contract toxoplasmosis if they eat undercooked infected duck meat or come into contact with contaminated duck feces.
Ingesting just a small number of T. gondii oocysts or tissue cysts can lead to toxoplasmosis infection in humans. Symptoms are flu-like including muscle aches, headaches, fever, and fatigue. Toxoplasmosis can also be transmitted congenitally from mother to fetus resulting in serious birth defects or developmental disorders. Properly cooking duck meat to an internal temperature of 165°F kills tissue cysts and prevents transmission.
Toxoplasmosis cases potentially associated with Muscovy duck exposure
- 2001 outbreak in Brazil, 179 people infected
- 2009 case study of a 27 year old man in China
- 2015 case study of a 52 year old woman in Turkey
Conclusion
Muscovy ducks can carry a variety of potentially zoonotic diseases transmissible to humans. These include avian influenza, salmonellosis, botulism, psittacosis, and toxoplasmosis. However, the risks of disease transmission are relatively low for most people with casual exposure to Muscovy ducks.
Practicing proper hygiene around ducks and avoiding contact with duck feces reduces infection risks. Thoroughly cooking duck meat and eggs also kills many potential pathogens. For backyard duck owners, providing clean enclosures, preventing contact with wild ducks, and getting routine veterinary testing helps limit spread of duck diseases. With appropriate precautions and care, the benefits of keeping Muscovy ducks can outweigh the small risks of disease.
