Introduction to Zoonoses, Emerging Infectious Diseases, and One Health

Comprehensive vocabulary review flashcards covering principles of zoonoses, epidemiological classifications, and bacterial, fungal, chlamydial, and rickettsial zoonotic diseases.

Zoonoses

Diseases that are transmissible from vertebrate animals to humans (derived from Greek 'zóon' meaning animal and 'nósos' meaning disease or unwell).

Epidemiological Triad

The foundational model of infectious disease causation comprising the interaction of Host, Agent, and Environment.

Definitive Host (Final Host)

A host in which an infectious agent reaches maturity.

Primary Host

A host that maintains an infection in endemic areas.

Secondary Host

A host that is additionally involved in the life cycle of an agent in non-endemic areas.

Paratenic Host

A host in which an infectious agent is transferred mechanically without undergoing development.

Intermediate Host

A host in which essential developmental stages of the infectious agent take place.

Amplifier Host

A host in which an infectious agent replicates rapidly, increasing the amount of agent available for transmission.

Hibernating Host

A host in which an infectious agent remains in a state of suspended animation.

Incidental Host

A host in which the infectious agent does not reach maturity.

Reservoir Host

A host that acts as a continuous, common source of infection for a pathogen.

Mechanical Vector

An invertebrate that physically transfers an infectious agent between hosts without the agent undergoing replication or development.

Biological Vector

An invertebrate vector in which an agent undergoes development (developmental), replication (propagative), or both (cyclopropagative).

Direct Zoonoses

Zoonoses that are maintained in nature and require only one vertebrate host species to complete the transmission cycle.

Cyclozoonoses

Zoonoses that require more than one vertebrate host species, but no invertebrate host, to complete the developmental cycle.

Metazoonoses

Zoonoses that require both vertebrate and invertebrate hosts (such as biological vectors) to complete the transmission cycle.

Saprozoonoses

Zoonoses that have a vertebrate host reservoir as well as a non-animal developmental site or reservoir such as soil, water, or decaying organic matter.

Anthropozoonoses

Zoonotic diseases transmitted primarily from lower vertebrate animals to humans.

Zooanthroponoses

Diseases that are primarily transmitted from humans to lower vertebrate animals.

Amphixenoses

Diseases maintained in nature that can be transmitted bidirectionally between humans and lower animals.

Xenozoonoses

Zoonotic infections transmitted from animals to humans via xenotransplantation (transplantation of animal tissues, organs, or cells).

Zoonotic Spillover

The transmission event wherein a pathogen is transmitted from a vertebrate animal population into a human host.

Spillover Bottleneck

Ecological, physical, or immunological barriers that either permit or constrain the flow of a pathogen between host species.

Colibacillosis

An infection caused by pathogenic strains of Escherichia coli, manifesting with cholera-like symptoms, watery diarrhea with a rice-wash appearance, vomiting, and cramps.

Hemolytic Uremic Syndrome (HUS)

A severe complication of Shiga toxin-producing E. coli (STEC) characterized by paleness, bruising, fatigue, anuria, and hematuria.

E. coli Surface Antigens

Structures used for serotyping E. coli strains: O antigen (somatic / cell wall), H antigen (flagellar), K antigen (capsular), and F antigen (fimbrial).

White Scour

A form of colibacillosis affecting young calves, primarily caused by enterotoxic Escherichia coli (ETEC).

Gut Edema

A condition in swine caused by infection with Shiga toxin-producing Escherichia coli (STEC).

Salmonellosis

A food-borne zoonosis caused by Salmonella enterica serovars (such as Typhi, Paratyphi, Enteritidis, and Typhimurium), presenting with fever, vomiting, diarrhea, stomach cramps, and myalgia.

Fowl Typhoid

An avian salmonellosis caused specifically by Salmonella enterica serovar Gallinarum.

Bacillary White Diarrhea

An avian bacterial infection caused by Salmonella enterica serovar Pullorum.

Listeriosis

A bacterial infection caused by Listeria monocytogenes (circling disease in animals), acquired through contaminated dairy or meat and causing cutaneous lesions, meningitis, and pregnancy complications.

Granulomatosis Infantiseptica

A severe form of neonatal listeriosis marked by generalized pustular lesions and septicemia.

Erysipeloid

A cutaneous bacterial infection caused by Erysipelothrix rhusiopathiae (also known as fish handler's disease or Rosenbach erysipeloid), characterized by an erythematous, edematous, purplish-red wound lesion.

Rhomboid Urticaria

Discrete, pink-to-purple diamond-shaped skin lesions seen in swine infected with Erysipelothrix rhusiopathiae (swine erysipelas).

Dermatophilosis

A skin disease caused by Dermatophilus congolensis (known as streptotrichosis, strawberry foot rot, or mycotic dermatitis in sheep), presenting as desquamative pustular dermatitis.

MRSA Infection

A soft tissue infection caused by Methicillin-resistant Staphylococcus aureus, presenting with localized red, swollen, painful, warm, pus-filled lesions that can become invasive.

Anthrax

A zoonosis caused by Bacillus anthracis (known as woolsorter's disease, charbon, or malignant pustule), occurring in cutaneous, respiratory, and gastrointestinal forms.

Cutaneous Anthrax

The skin form of Bacillus anthracis infection that manifests as an ulcerated lesion that develops into a characteristic depressed black eschar.

Anthrax Pathognomonic Signs in Animals

A diagnostic post-mortem triad: blood oozing from normal body orifices, an absence of rigor mortis, and rapid decomposition of the carcass.

Ascoli Test

The gold standard precipitation test used for the serological detection and diagnosis of anthrax.

Leptospirosis

A bacterial spirochetal zoonosis caused by Leptospira interrogans, transmitted through contact with water or soil contaminated by infected animal urine.

Weil's Disease

The severe icteric or hepatonephritic form of leptospirosis in humans, marked by jaundice, conjunctivitis, skin petechiation, and proteinuria.

Canicola Fever (Stuttgart's Disease)

Canine leptospirosis caused specifically by Leptospira interrogans serovar Canicola.

Milk Drop Syndrome

A bovine manifestation of leptospirosis causing a sudden decrease in milk yield and flaccid agalactia.

Microscopic Agglutination Test (MAT)

The gold standard serological laboratory test used to diagnose leptospirosis.

Brucellosis

A bacterial zoonosis caused by Brucella species (known as undulant fever or Malta fever in humans, and Bang's disease in cattle), featuring an irregular intermittent fever that peaks at noon and causes night sweats.

Rose Bengal Test

The gold standard rapid slide agglutination test used for screening and diagnosing brucellosis.

Plague

A high-mortality zoonotic infection caused by Yersinia pestis (known as Black Death or pestilential fever), transmitted by the Oriental black rat flea (Xenopsylla cheopis).

Buboes

Intensely painful, acutely inflamed peripheral lymph nodes pathognomonic of the bubonic form of plague.

Septicemic Plague

A bloodstream infection caused by Yersinia pestis leading to disseminated intravascular coagulopathy (DIC), acute respiratory distress syndrome (ARDS), and acral tissue necrosis.

Lyme Disease

A tick-borne zoonosis caused by Borrelia burgdorferi, transmitted by the bite of Ixodes dammini (deer tick) attached for at least $2\,\text{hours}$.

Erythema Chronicum Migrans (ECM)

A pathognomonic 'bull's-eye' cutaneous lesion that expands radially from the site of a tick bite in Lyme disease.

Glanders

A zoonotic bacterial disease of equids caused by Burkholderia mallei (also known as farcy or maliasmus), causing nostril ulceration, mucopurulent discharge, and nodular abscesses.

Pasteurellosis

A bacterial infection caused by Pasteurella multocida and related species, transmitted via animal bites or scratches, and causing shipping fever, haemorrhagic septicemia, or snuffles in animals.

Cat Scratch Disease

A bacterial infection caused by Bartonella henselae, transmitted through cat bites or scratches, and presenting with regional lymphadenopathy without lymphadenitis.

Parinaud's Oculoglandular Syndrome

A complication of cat scratch disease presenting with a unilateral conjunctival granuloma and regional preauricular or submandibular lymphadenopathy.

Rat Bite Fever

A systemic febrile illness transmitted through rodent bites, caused by either Streptobacillus moniliformis (Haverhill fever) or Spirillum minus (Sodoku).

Sodoku

The spirillary form of rat bite fever caused by Spirillum minus, marked by recurrent fever, exanthema, and local induration at the bite site.

Tularemia

A zoonotic infection caused by Francisella tularensis (known as rabbit fever or deer fly fever), acquired from contact with infected rabbits or squirrels and occurring in ulceroglandular, glandular, oculoglandular, pulmonary, or typhoid forms.

Thermally Dimorphic Fungi

Fungi that shift their morphological structure depending on temperature, growing as a mycelial/mold form at ambient temperatures and as a yeast form at body temperature.

Coccidioidomycosis

A systemic fungal disease caused by Coccidioides immitis (known as San Joaquin Valley Fever or Desert Fever), contracted via inhalation of spores from soil or animal feces in North and South America.

Valley Fever Triad

The clinical triad seen in primary coccidioidomycosis, comprising arthritis, conjunctivitis, and erythema nodosum or erythema multiforme rash.

Histoplasmosis

A mycotic infection caused by Histoplasma capsulatum (known as Darling disease or cave disease), acquired by inhaling microconidia from bird or bat droppings.

Presumed Ocular Histoplasmosis Syndrome (POHS)

An ocular complication of Histoplasma capsulatum infection that can cause vision loss.

Cryptococcosis

An opportunistic fungal disease caused by encapsulated Cryptococcus neoformans, shed in pigeon feces and manifesting as pulmonary disease or cryptococcal meningitis.

Dermatophytosis

A superficial fungal infection of keratinized tissue (skin, hair, claws) caused by dermatophytes such as Microsporum canis, Trichophyton equinum, and Trichophyton verrucosum (ringworm or tinea).

Wood's Lamp Examination

A diagnostic procedure using ultraviolet light to detect apple-green fluorescence on hair or skin infected by dermatophytes such as Microsporum canis.

Avian Chlamydiosis

A zoonosis caused by Chlamydophila psittaci (psittacosis or parrot fever), acquired by inhaling contaminated feather dust or droppings, and causing respiratory signs and greenish droppings in birds.

Levinthal-Cole-Lillie (LCL) Bodies

Characteristic basophilic intracytoplasmic inclusion bodies observed in host cells infected with Chlamydophila psittaci.

Chlamydia abortus Infection

A chlamydial infection causing enzootic abortion in sheep and goats, which poses a severe risk of abortion, stillbirth, and preterm labor in pregnant women.

Rocky Mountain Spotted Fever (RMSF)

A tick-borne rickettsiosis caused by Rickettsia rickettsii, transmitted by Dermacentor and Amblyomma ticks, presenting with sustained fever, chills, myalgia, and a spotted rash.

Human Ewingii Ehrlichiosis

A tick-borne disease caused by Ehrlichia ewingii, maintained in dogs and transmitted to humans via the bite of the lone star tick (Amblyomma americanum).

Human Monocytic Ehrlichiosis (HME)

An intracellular infection caused by Ehrlichia chaffeensis, maintained in cervids and transmitted to humans by tick bites.

Human Granulocytic Anaplasmosis (HGA)

A tick-borne infection caused by Anaplasma phagocytophilum, maintained in wild rodents and deer and transmitted by Ixodes ticks.

Sennetsu Fever

A rickettsial disease caused by Neorickettsia sennetsu in East and Southeast Asia, transmitted by ingesting raw fish harboring infected trematodes.

Scrub Typhus

A zoonosis caused by Orientia tsutsugamushi (Tsutsugamushi disease), transmitted by the bite of trombiculid mites (Neoschongastia americana / chiggers), forming a cutaneous eschar.

Q Fever

A zoonotic infection caused by Coxiella burnetii (Query fever or coxiellosis), transmitted via inhalation of barnyard dust or contact with infected placenta, milk, urine, or feces, causing late-term abortions in ruminants.