Chapter 29 Multisystem Zoonoses Flashcards
A non-human vertebrate host is the reservoir of infection and humans are involved only incidentally
Dead end host
Do multisystem zoonoses infections have human to human transmission?
No except for Ebola
An Enveloped, Negative-sense ssRNA virus with 2 RNA strands (____ means ‘sandy’ in Latin—contains ribosomes on genome)
Arenavirus
IN 1962, Patients developed Fever Myalgia enanthem (internal rash) capillary leakage hemorrhage, shock and a neurological illness mortality rate of 15%
Bolivian Hemorrhagic Fever
What is the transmission for Bolivian Hemorrhagic fever?
DDT spraying for malaria-> DDT in insects eaten by geckos-> eaten by cats-> cats die-> this allows bush mice to thrive-> Machupo virus harmless in mice-> infects humans
In central and east Africa
caused by ___ virus (EBOV) and ____virus
Filoviridae— long filamentous Neg-sense ssRNA viruses
Ebola and Marburg Hemorrhagic Fevers
What are the 5 Ebola viruses?
Zaire virus Sudan virus Tai Forest virus Bundibugyo virus Reston virus -infects primates only
What are the Ebola viruses caused by?
Fruit bats
Discovered in 1976 near the Ebola River in the Democratic Republic of Congo
Affects People, monkeys, gorillas and chimpanzees
Transmitted by direct contact with bodily fluids
Enters body through broken skin, mucus membranes in the eye, nose and mouth
Found in semen in men that survived (up to 7 weeks)
Ebola virus
Treatment for Ebola
Providing fluids and electrolytes (body salts) through infusion into the vein (intravenously).
Offering oxygen therapy to maintain oxygen status.
Using medication to support blood pressure, reduce vomiting and diarrhea and to manage fever and pain.
What is recovery like for Ebola?
develop antibodies that can last 10 years, possibly longer. Some survivors may have long-term complications, such as joint and vision problems.
How do you diagnose Ebola?
PCR
obligate intracellular, gram-neg. coccobacilli
Primary Reservoir: cattle, sheep, goats
Infection by inhallation of organism from contaminated
sources (placenta, dust in barns, raw milk)
Coxiella burnetii
What causes query fever?
coxiella burnetii
Bacterium is highly resistant to heat and drying
Killed by pasteurization
Infection: multiplies in lungs; 3-30day incubation period (50% develop symptoms: high fever, headache, muscle aches, nausea, vomiting, diarrhea—treat with antibiotics)
Complication: Chronic phase: endocarditis; Mortality 50% untreated; 5% treated
coxiella
aerobic, non-motile,
gram-positive spore forming rod
disease of herbivores such as sheep, goats, cattle and horses, and bacilli are excreted in feces, urine and saliva.
Spores (bacteria) enter body via broken skin and mucus membranes and less commonly the respiratory tract (used as bioterrorism)
Anthrax
What is anthrax caused by?
Bacillus anthracis
Bacteria multiply at site of entry, produce anthrax
Toxin, The toxin accumulates: 12-36h a papule
develops, then ulcerates, the center becomes
black and necrotic (eschar)
anthrax
What is the treatment of anthrax?
antibiotics and antitoxin
is successfully treated by ciprofloxacin?
Cutaneous anthrax
treated with combination antimicrobial therapy plus antitoxin.
Systemic anthrax
ingestion of spores, fever, chills, diarrhea (may be bloody), headache, sore throat, stomach pain
(25-75% death rate)
Gastrointestinal anthrax
When the spores are inhaled and enter alveolar macrophages, bacterial growth in the lung leads to pulmonary edema and mediastinal hemorrhage, with spread to the blood and subsequent death (up to 80%). (referred to as ‘woolsorter’s disease’)
Pulmonary anthrax
gram-negative, facultative anaerobic, non-motile rod (with an antiphagocytic capsule)
Reservoir: rodents (rats, mice, gerbils)-mild infection
Spread by fleas
In the 14th century: 25% of Europe’s population died in plague epidemics (about 25 million deaths)
plague
what causes the plague?
yersinia pestis
caused by flea bite
Bacteria multiply at site of bite
Spread to local/regional lymph nodes
Produce virulence factors (endotoxin and other toxins)
2-6 days after bite: fever, headache, chills, weakness
Lymph nodes become swollen, painful, tender “Buboes” with hemorrhagic inflamation
Treatment: antibiotics
Death rate: 50% untreated
bubonic plague
Patients develop fever, chills, extreme weakness, abdominal pain, shock, and possibly bleeding into the skin and other organs. Skin and other tissues may turn black and die, especially on fingers, toes, and the nose. (100% death untreated)
septicemic plague
Incubaton period: as short as 24h. bacteria replicate in lungs, can spread from person to person via droplets. Fever, headache, weakness, pneumonia (may have bloody or watery mucus). 100% death if untreated
pneumonic plague
how do you treat the plague?
streptomycin
aerobic, gram-negative, non-motile, intracellular, coccobacilli
Brucella sp
infects cows worldwide, but has been eliminated from several resource-rich countries. It causes mild disease in humans.
b. abortus
infects goats and sheep and is common in Malta and other Mediterranean countries, Mexico and South America. It causes more severe disease in humans.
b. melitensis
infects pigs in the USA, South America, and SE Asia. It causes severe disease with destructive lesions in humans.
b. suis
infects dogs and is an uncommon cause of mild disease in humans.
b. canis
In cows and goats, ____ localize in the placenta, causing abortion, and also in mammary glands (shed for long periods in milk). They are present in uterine discharges, faeces and urine.
brucellae
occurs when the bacteria enter the body via abrasions in the skin, via the alimentary tract or, most commonly, via the respiratory tract.
Infection is therefore more common in farmers, veterinarians and abattoir workers
Clinical features: bacteria replicate from site of entry move to lymph nodes, travel to blood (septicemic phase), infects liver, spleen, bone marrow, lymphoid tissues) and can survive for prolonged periods.
Symptoms: 2-6 weeks after infection; subclinical or fever, malaise, aching, weakness (undulant fever in some), may develop hepatitis
Human brucellosis (undulant fever, Malta fever)
Brucellosis symptoms may disappear for weeks or months and then return. In some people, brucellosis becomes chronic, with symptoms persisting for years, even after treatment. Long-term signs and symptoms may include fatigue, recurrent fevers, arthritis, swelling of the heart (endocarditis) and spondylitis — an inflammatory arthritis that affects the spine and adjacent joints.
Undulant fever
Diagnosis of brucellosis
blood culture; antibodies
Treatment of brucellosis
antibiotics for 6 weeks or maybe months