Natural reservoir or
nidus, refers to the long-term
hostIn biology, a host is an organism that harbors a parasite, or a mutual or commensal symbiont, typically providing nourishment and shelter. In botany, a host plant is one that supplies food resources and substrate for certain insects or other fauna...
of the
pathogenA pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
of an
infectious diseaseInfectious diseases, also known as communicable diseases, contagious diseases or transmissible diseases comprise clinically evident illness resulting from the infection, presence and growth of pathogenic biological agents in an individual host organism...
. It is often the case that hosts do not get the disease carried by the pathogen or it is carried as a
subclinical infectionA subclinical infection is the asymptomatic carrying of an by an individual of an agent that usually is a pathogen causing illness, at least in some individuals. Many pathogens spread by being silently carried in this way by some of their host population...
and so
asymptomaticIn medicine, a disease is considered asymptomatic if a patient is a carrier for a disease or infection but experiences no symptoms. A condition might be asymptomatic if it fails to show the noticeable symptoms with which it is usually associated. Asymptomatic infections are also called subclinical...
and non-lethal. Once discovered, natural reservoirs elucidate the complete life cycle of infectious diseases, providing effective
preventionPreventive medicine or preventive care refers to measures taken to prevent diseases, rather than curing them or treating their symptoms...
and control. Examples of natural reservoirs are:
- Field mice
Apodemus is the genus of Muridae which contains the Eurasian field mice. Related to the Ryūkyū spiny rats and the prehistoric Rhagamys – and far more distantly to Mus and Malacomys –, it includes the following species:*Striped Field Mouse, Apodemus agrarius*Alpine Field Mouse, Apodemus...
, for hantavirusHantaviruses are negative sense RNA viruses in the Bunyaviridae family. Humans may be infected with hantaviruses through rodent bites, urine, saliva or contact with rodent waste products...
es and Lassa feverLassa fever is an acute viral hemorrhagic fever caused by the Lassa virus and first described in 1969 in the town of Lassa, in Borno State, Nigeria, in the Yedseram river valley at the south end of Lake Chad. Clinical cases of the disease had been known for over a decade but had not been connected...
- Marmot
The marmots are a genus, Marmota, of squirrels. There are 14 species in this genus.Marmots are generally large ground squirrels. Those most often referred to as marmots tend to live in mountainous areas such as the Alps, northern Apennines, Eurasian steppes, Carpathians, Tatras, and Pyrenees in...
s, black ratThe black rat is a common long-tailed rodent of the genus Rattus in the subfamily Murinae . The species originated in tropical Asia and spread through the Near East in Roman times before reaching Europe by the 1st century and spreading with Europeans across the world.-Taxonomy:The black rat was...
s, prairie dogPrairie dogs are burrowing rodents native to the grasslands of North America. There are five different species of prairie dogs: black-tailed, white-tailed, Gunnison's, Utah and Mexican prairie dogs. They are a type of ground squirrel, found in the United States, Canada and Mexico...
s, chipmunkChipmunks are small striped squirrels native to North America and Asia. They are usually classed either as a single genus with three subgenera, or as three genera.-Etymology and taxonomy:...
s and squirrelSquirrels belong to a large family of small or medium-sized rodents called the Sciuridae. The family includes tree squirrels, ground squirrels, chipmunks, marmots , flying squirrels, and prairie dogs. Squirrels are indigenous to the Americas, Eurasia, and Africa and have been introduced to Australia...
s for bubonic plaguePlague is a deadly infectious disease that is caused by the enterobacteria Yersinia pestis, named after the French-Swiss bacteriologist Alexandre Yersin. Primarily carried by rodents and spread to humans via fleas, the disease is notorious throughout history, due to the unrivaled scale of death...
- Armadillo
Armadillos are New World placental mammals, known for having a leathery armor shell. Dasypodidae is the only surviving family in the order Cingulata, part of the superorder Xenarthra along with the anteaters and sloths. The word armadillo is Spanish for "little armored one"...
s and opossums for Chagas diseaseChagas disease is a tropical parasitic disease caused by the flagellate protozoan Trypanosoma cruzi. T. cruzi is commonly transmitted to humans and other mammals by an insect vector, the blood-sucking insects of the subfamily Triatominae most commonly species belonging to the Triatoma, Rhodnius,...
and several species of New WorldThe New World is one of the names used for the Western Hemisphere, specifically America and sometimes Oceania . The term originated in the late 15th century, when America had been recently discovered by European explorers, expanding the geographical horizon of the people of the European middle...
LeishmaniaLeishmania is a genus of Trypanosomatid protozoa, and is the parasite responsible for the disease leishmaniasis. It is spread through sandflies of the genus Phlebotomus in the Old World, and of the genus Lutzomyia in the New World. Their primary hosts are vertebrates; Leishmania commonly infects...
- Tick
Ticks are small arachnids in the order Ixodida, along with mites, constitute the subclass Acarina. Ticks are ectoparasites , living by hematophagy on the blood of mammals, birds, and sometimes reptiles and amphibians...
s for babesiosisBabesiosis is a malaria-like parasitic disease caused by infection with Babesia, a genus of protozoal piroplasms. After trypanosomes, Babesia are thought to be the second most common blood parasites of mammals and they can have a major impact on health of domestic animals in areas without severe...
and Rocky Mountain spotted feverRocky Mountain spotted fever is the most lethal and most frequently reported rickettsial illness in the United States. It has been diagnosed throughout the Americas. Some synonyms for Rocky Mountain spotted fever in other countries include “tick typhus,” “Tobia fever” , “São Paulo fever” or “febre...
- Ground squirrels, porcupine
Porcupines are rodents with a coat of sharp spines, or quills, that defend or camouflage them from predators. They are indigenous to the Americas, southern Asia, and Africa. Porcupines are the third largest of the rodents, behind the capybara and the beaver. Most porcupines are about long, with...
s, and chipmunks for Colorado tick feverColorado Tick Fever is an obtuse viral infection transmitted from the bite of an infected tick...
- Mosquito
Mosquitoes are members of a family of nematocerid flies: the Culicidae . The word Mosquito is from the Spanish and Portuguese for little fly...
es for filariasisFilariasis is a parasitic disease and is considered an infectious tropical disease, that is caused by thread-like nematodes belonging to the superfamily Filarioidea, also known as "filariae"....
and malariaMalaria is a mosquito-borne infectious disease of humans and other animals caused by eukaryotic protists of the genus Plasmodium. The disease results from the multiplication of Plasmodium parasites within red blood cells, causing symptoms that typically include fever and headache, in severe cases...
- Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...
s for schistosomiasisSchistosomiasis is a parasitic disease caused by several species of trematodes , a parasitic worm of the genus Schistosoma. Snails often act as an intermediary agent for the infectious diseases until a new human host is found...
and swimmer's itchSwimmer’s itch, also known as lake itch, duck itch, cercarial dermatitis, and Schistosome cercarial dermatitis, is a short-term, immune reaction occurring in the skin of humans that have been infected by water-borne schistosomatidae...
- Pig
A pig is any of the animals in the genus Sus, within the Suidae family of even-toed ungulates. Pigs include the domestic pig, its ancestor the wild boar, and several other wild relatives...
s for cestodeThis article describes the flatworm. For the medical condition, see Tapeworm infection.Cestoda is the name given to a class of parasitic flatworms, commonly called tapeworms, of the phylum Platyhelminthes. Its members live in the digestive tract of vertebrates as adults, and often in the bodies...
worm infections
- Raccoons, skunks, fox
Fox is a common name for many species of omnivorous mammals belonging to the Canidae family. Foxes are small to medium-sized canids , characterized by possessing a long narrow snout, and a bushy tail .Members of about 37 species are referred to as foxes, of which only 12 species actually belong to...
es and batBats are mammals of the order Chiroptera "hand" and pteron "wing") whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, glide rather than fly,...
s for rabiesRabies is a viral disease that causes acute encephalitis in warm-blooded animals. It is zoonotic , most commonly by a bite from an infected animal. For a human, rabies is almost invariably fatal if post-exposure prophylaxis is not administered prior to the onset of severe symptoms...
- Shellfish
Shellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found only in freshwater...
for choleraCholera is an infection of the small intestine that is caused by the bacterium Vibrio cholerae. The main symptoms are profuse watery diarrhea and vomiting. Transmission occurs primarily by drinking or eating water or food that has been contaminated by the diarrhea of an infected person or the feces...
- Fowl
Fowl is a word for birds in general but usually refers to birds belonging to one of two biological orders, namely the gamefowl or landfowl and the waterfowl...
(duckDuck is the common name for a large number of species in the Anatidae family of birds, which also includes swans and geese. The ducks are divided among several subfamilies in the Anatidae family; they do not represent a monophyletic group but a form taxon, since swans and geese are not considered...
s and geeseThe word goose is the English name for a group of waterfowl, belonging to the family Anatidae. This family also includes swans, most of which are larger than true geese, and ducks, which are smaller....
) for avian influenza
- Bat
Bats are mammals of the order Chiroptera "hand" and pteron "wing") whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, glide rather than fly,...
s, the reservoir for nipah, hendraHendra may refer to:People* Hendra Aprida Gunawan , male badminton player* Hendra Setiawan , badminton player* Imay Hendra, badminton player* Tony Hendra , British actor and authorOther* Hendra, Cornwall...
, rabiesRabies is a viral disease that causes acute encephalitis in warm-blooded animals. It is zoonotic , most commonly by a bite from an infected animal. For a human, rabies is almost invariably fatal if post-exposure prophylaxis is not administered prior to the onset of severe symptoms...
and severe acute respiratory syndromeSevere Acute Respiratory Syndrome is a respiratory disease in humans which is caused by the SARS coronavirus . Between November 2002 and July 2003 an outbreak of SARS in Hong Kong nearly became a pandemic, with 8,422 cases and 916 deaths worldwide according to the WHO...
(SARS)
- Dog
The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...
s and wild canids for Leishmania infantumLeishmania infantum is the causative agent of infantile visceral leishmaniasis in the Mediterranean region of the Old World and in Latin America, where it has been called Leishmania chagasi. It is also an unusual cause of cutaneous leishmaniasis. Wild canids and domestic dogs are the natural...
, the cause of infantile visceral leishmaniasisVisceral leishmaniasis , also known as kala-azar, black fever, and Dumdum fever, is the most severe form of leishmaniasis. Leishmaniasis is a disease caused by protozoan parasites of the Leishmania genus. This disease is the second-largest parasitic killer in the world , responsible for an...
- Cat
The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...
s, for BartonellaBartonella is a genus of Gram-negative bacteria. Facultative intracellular parasites, Bartonella species can infect healthy people but are considered especially important as opportunistic pathogens. Bartonella are transmitted by insect vectors such as ticks, fleas, sand flies and mosquitoes...
(aka Cat scratch diseaseCat scratch disease is a usually benign infectious disease caused by the intracellular bacterium Bartonella. It is most commonly found in children following a scratch or bite from a cat by about one to two weeks...
)
- Gerbil
A gerbil is a small mammal of the order Rodentia. Once known simply as "desert rats", the gerbil subfamily includes about 110 species of African, Indian, and Asian rodents, including sand rats and jirds, all of which are adapted to arid habitats...
s for Leishmania majorLeishmania major is a species of Leishmania.It is associated with zoonotic cutaneous leishmaniasis.The genome has been sequenced....
, the causative agent of cutaneous leishmaniasisCutaneous leishmaniasis is the most common form of leishmaniasis. It is a skin infection caused by a single-celled parasite that is transmitted by sandfly bites...
in the Old WorldThe Old World consists of those parts of the world known to classical antiquity and the European Middle Ages. It is used in the context of, and contrast with, the "New World" ....
- Rock hyrax for Leishmania aethiopica
Leishmania is a Leishmania species.It is associated with leishmaniasis....
and, probably, certain strains of Leishmania tropicaLeishmania tropica is a species of flagellate parasites that infects humans and rodents. It can cause a disease called oriental sore which is a form of cutaneous leishmaniasis.Leishmania tropica is a single-celled trypanosome parasite responsible for causing cutaneous Leishmaniasis.[1]...
, the causative agents of cutaneous leishmaniasisCutaneous leishmaniasis is the most common form of leishmaniasis. It is a skin infection caused by a single-celled parasite that is transmitted by sandfly bites...
in the Old WorldThe Old World consists of those parts of the world known to classical antiquity and the European Middle Ages. It is used in the context of, and contrast with, the "New World" ....
Some diseases have no non-human reservoir:
poliomyelitisPoliomyelitis, often called polio or infantile paralysis, is an acute viral infectious disease spread from person to person, primarily via the fecal-oral route...
and
smallpoxSmallpox was an infectious disease unique to humans, caused by either of two virus variants, Variola major and Variola minor. The disease is also known by the Latin names Variola or Variola vera, which is a derivative of the Latin varius, meaning "spotted", or varus, meaning "pimple"...
are prominent examples.
The natural reservoir of some diseases remain unknown. This is the case of the
EbolaEbola virus disease is the name for the human disease which may be caused by any of the four known ebolaviruses. These four viruses are: Bundibugyo virus , Ebola virus , Sudan virus , and Taï Forest virus...
disease, which is caused by a virus.