BRUCELLOSIS, MARINE MAMMAL - USA: (MAINE) PORPOISE
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Date: Thu 28 Jun 2012
Source: My Health News Daily [edited]
<http://www.myhealthnewsdaily.com/2777-marine-mammal-disease-cdc.html?>
A dead harbor porpoise that washed up in Maine in January turned out to be carrying a disease-causing bacteria that could have sickened the people who handled the animal, according to a report today (28 June
2012) from the Centers for Disease Control and Prevention.
The case serves as a reminder of the potential for infection when rescuing or handling marine mammals, and the importance of using proper protection to avoid exposure to diseases, the researchers said in their report.
The bacteria found in the porpoise, called _Brucella_, causes flu-like symptoms in people, including fever, sweats, headache, back pain and weakness, which can persist for years, according to the CDC.
Sometimes, the bacteria cause severe infections of the brain, bone, heart, liver or spleen, the CDC says.
After the carcass of the porpoise was recovered on 29 January 2012, a university faculty member, 2 students and a community volunteer performed a necropsy on the animal. Although the team members wore gloves, they did not wear any protection over their noses and mouths to prevent themselves from breathing in the bacteria. (_Brucella_ can become airborne during a necropsy.)
Subsequent lab testing on samples from the porpoise revealed it was infected with _Brucella_.
Because the 4 people who performed the necropsy did not wear respiratory protection, they were considered at high risk for _Brucella_ infection, and were required to take antibiotics for 3 weeks, check themselves daily for fevers, and undergo weekly blood tests performed by CDC personnel. After 24 weeks, none of the individuals had become ill (signs of the disease can show up months after a person becomes infected).
"Persons who handle marine mammals should be educated on the potential for infection associated with their activities and the precautions necessary to avoid being exposed to infectious agents," the CDC researchers wrote. "Failure to use primary protection to avoid exposure necessitates using more costly and time-consuming secondary strategies."
Facilities that allow students and volunteers to participate in the rescue and handling of marine mammals should provide the same level of training and protection for this population as they do for their employees, the CDC said. _Brucella_ is not common in the United States, but is endemic in many parts of the world, according to the CDC. It is found in animals, including cattle, swine, goats and sheep.
Between 2000 and 2009, an average of 113 cases of brucellosis a year, the disease caused by _Brucella_, were reported to the CDC.
The new report will be published tomorrow (June 29) in the CDC's Morbidity and Mortality Week's Report.
Pass it on: Marine mammals can harbor infectious diseases, and people who rescue or handle them should use proper protection.
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Promed Mail from Health map alerts
[_Brucella_ infections have recently been recognized in seals, sea lions, walruses, dolphins, porpoises, whales and an otter. This organism appears to be widespread in marine mammals, and has probably been endemic in these populations for a long time. The clinical significance is uncertain. A few infections have been associated with placentitis/abortions, neonatal mortality, meningoencephalitis, abscesses or other syndromes, but _Brucella_ has also been isolated from normal tissues and asymptomatic animals. There are concerns that brucellosis might affect reproduction or echolocation, particularly in threatened species or naive populations.
Marine mammal isolates of _Brucella_ can infect terrestrial mammals, but the frequency of this event is unknown. Some polar bears, which feed on marine mammals, are seropositive for _Brucella_, and there are concerns about possible impacts on this species. Experimental infections in cattle and sheep have been described. Rare human infections have also been documented. One marine mammal isolate caused acute brucellosis in a researcher. Three other infected people had no occupational exposure to marine mammals; two individuals had neurological signs, and the third developed spinal osteomyelitis.
Marine mammal _Brucella_ isolates are genetically distinct from terrestrial species, and if the traditional naming system is continued, they are expected to receive species names. _B. maris_ was originally suggested for all marine mammal strains of __Brucella__, with division into 2 or more biovars based on host specificity.
(Biovar 1 would contain seal and otter isolates, and biovar 2 would contain cetacean isolates.) A more recent proposal suggests division into at least 2 species: _B. pinnipediae_ for strains from pinnipeds (seals, sea lions and walruses) and _B. cetaceae_ for isolates from cetaceans (whales, porpoises and dolphins). Another scheme suggests a division into 3 distinct groups comprised of isolates from seals, porpoises and dolphins.
Currently, there is little or no information about the significance of infection in each species. _Brucella_ has been found in asymptomatic animals, stranded or dead animals with lesions and, rarely, animals that are ill. _Brucella_ may be endemic in populations that have a high seroprevalence, such as hooded seals and dusky dolphins, and an incidental infection in other species.
Terrestrial species can be infected with marine mammal isolates, probably as incidental hosts. Antibodies to _Brucella_ have been found in polar bears; these antibodies are thought to result from exposure to infected seals and other prey. Experimental infections with marine mammal isolates have been described in cattle, sheep and guinea pigs, and unpublished experiments suggest that piglets can be infected transiently. Symptomatic infections have also been described in humans.
Transmission of _Brucella_ is poorly understood in marine mammals, with little direct evidence to support any route of infection.
Terrestrial species of _Brucella_ are often transmitted by exposure to the infected placenta, birth fluids and vaginal secretions, and by venereal spread. These routes may also occur in marine mammals; _Brucella_ has been isolated from the reproductive organs of cetaceans. Transmission in milk or in utero may be possible. The survival of marine isolates in the environment has not been studied; however, terrestrial species of _Brucella_ can remain viable for several months in water and on some fomites, particularly when the temperature is low.
The frequency and route of transmission to humans and other terrestrial mammals is unknown. Predation on infected seals has been suggested as a possible route of exposure for polar bears. Cattle have been infected experimentally by intravenous injection, and cattle and sheep by intraconjunctival inoculation. One human infection occurred after exposure in the laboratory, but the source of 3 other infections is unknown. Humans usually become infected with terrestrial species of _Brucella_ by ingesting organisms in food, or by the contamination of mucous membranes and abraded skin.
No clinical syndrome has been established for brucellosis in marine mammals. Limited evidence suggests that this organism can be considered in abortions, orchitis, epididymitis, abscesses, meningitis/meningoencephalitis and systemic disease. _Brucella_ has been found in apparently normal as well as symptomatic animals.
In dolphins with meningitis, the differential diagnosis includes parasitism (_Nasitrema_ sp.), staphylococcal infection, and herpesvirus and morbillivirus infections. Other diseases causing abortions, orchitis, epididymitis, abscesses and systemic disease should be considered in marine mammals with these syndromes and evidence of _Brucella_ infection.
Humans have been infected with marine mammal isolates of _Brucella_; samples should be collected and handled with all appropriate precautions.
_Brucella_ has been isolated from all major body tissues in marine mammals. In particular, this organism has been found in the male and female reproductive organs, mammary gland, abscesses, lung and a variety of lymph nodes. Oral, nasal, tracheal, vaginal and anal swabs, as well as feces, can be submitted for culture from live animals.
Serum should also be collected for serology. At necropsy, samples should be collected from all tissues with gross lesions. Other samples may also be taken; _Brucella_ has been isolated from tissues with microscopic but no gross lesions, as well as tissues without lesions.
Blood cultures collected from the heart are occasionally successful at necropsy.
Zoonotic infections with marine mammal strains may be similar to infections with terrestrial strains. In humans, most species of _Brucella_ cause similar syndromes. Infections can be either asymptomatic or symptomatic. In symptomatic cases, the disease is extremely variable and the clinical signs may appear insidiously or abruptly. Typically, human brucellosis begins as an acute febrile illness with nonspecific flu-like signs such as fever, headache, malaise, back pain, myalgia and generalized aches. Drenching sweats can occur, particularly at night. Some patients recover spontaneously, while others develop persistent symptoms that typically wax and wane.
Occasionally seen complications include arthritis, spondylitis, chronic fatigue, and epididymo-orchitis. Neurologic signs (including personality changes, meningitis, uveitis and optic neuritis), anemia, internal abscesses, nephritis, endocarditis and dermatitis can also occur. Neurological signs usually occur in less than 5% of patients.
Other organs and tissues can also be affected, resulting in a wide variety of syndromes. Treatment is with antibiotics; however, relapses can be seen months after the initial symptoms, even in successfully treated cases. The mortality rate is low; in untreated persons, estimates of the case fatality rate vary from less than 2 percent to 5 percent. Deaths are usually caused by endocarditis or meningitis.
Portions of this comment have been extracted from:
<http://www.cfsph.iastate.edu/Factsheets/pdfs/brucellosis_marine.pdf>
The entire article from the factsheet is well worth the reading. - Mod.TG
]
[see also:
Brucellosis, marine mammals 19960625.1166] .................................................sb/tg/ml/ll
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