Date: June 9, 2003
Source: New York Times
Abstract: Monkeypox, a viral disease related to smallpox but less infectious and less deadly, has been detected for the first time in the Americas, with at least 23 cases reported in three Midwestern states, the Centers for Disease Control and Prevention said yesterday.
Wisconsin reported 18 cases (15 suspected and 3 confirmed); Illinois reported four (one confirmed); and Indiana reported a single case. The patients ranged in age from 4 to 48 and became ill from May 15 to June 3. All had had direct or close contact with ill prairie dogs, which have become a fad in the exotic-pet market and which might have caught monkeypox from another species, possibly Gambian giant pouched rats; the rats are imported as pets from West or Central Africa, where the disease has long occurred. Monkeypox in Africa is carried mainly by squirrels but named after monkeys because it often kills them.
Several patients in the American outbreak work for veterinarians or pet stores that sold prairie dogs and Gambian rats. No patients have died and four have been hospitalized. Laboratory tests performed at the disease centers in Atlanta yesterday confirmed that the patients had been infected with the monkeypox virus, which belongs to the same orthopox family that includes the virus that causes smallpox.
The monkeypox patients typically fell ill with signs and symptoms like fever, headaches, dry cough, swollen lymph nodes, chills and drenching sweats, Wisconsin health officials said. One to 10 days later, the patients developed rashes consisting of blisterlike pimples that filled with pus, broke open and produced scabs. The rash often erupted in different stages, or crops, as it appeared on the head, trunk and arms and legs. Monkeypox lesions can scar the skin like smallpox or chickenpox.
Most monkeypox patients became ill 4 to 12 days after exposure to a sick animal, but the incubation period may have been as long as 20 days.
The federal disease centers issued a health alert about monkeypox on Saturday night in part out of its concern that doctors who had treated the cases had initially mistaken some for smallpox and chickenpox, said Dr. Stephen M. Ostroff, an epidemiologist at the agency.
Another concern was quickly alerting the public because the cases occurred so recently and because more people could be infected from diseased animals sold in recent days.
By quickly identifying the animals that can be infected with monkeypox, health officials hope to eliminate them before the disease becomes endemic in this country and in the Americas, Dr. Ostroff said. For this and other reasons, the disease centers advised people not to release into the wild live animals suspected of being infected with monkeypox.
Smallpox vaccination can protect against monkeypox, but at least one patient in the current outbreak in this country had been vaccinated for smallpox before routine vaccination was discontinued in 1972.
The disease agency has not recommended a ban on sales of prairie dogs and Gambian rats because the agency is still "in an information-gathering stage," Dr. Ostroff said. But two states, Illinois and Wisconsin, have acted to end their sale and distribution. On Friday afternoon, Wisconsin officials issued a quarantine prohibiting importation, sale and movement of prairie dogs received after April 1 and any nonhuman mammals that come in contact with them. On Saturday night, Gov. Rod R. Blagojevich of Illinois signed an executive order prohibiting sales, import or even public display of these animals.
The federal disease agency is asking physicians, veterinarians and the public to report to their local health departments any rash that develops in people within 21 days of their being exposed to prairie dogs, Gambian rats or other animals.
The agency advised hospital workers caring for suspected monkeypox patients to follow standard infection control measures, including the gloves, gowns and N-95 masks that have been used to protect against SARS. The agency also advised veterinarians to take the same precautions in caring for sick prairie dogs, Gambian rats, other rodents and rabbits.
Monkeypox has long been known to cause sporadic infections in the jungles of West and Central Africa. A sputtering outbreak has been occurring in recent years in Congo.
Up to 10 percent of monkeypox cases have been fatal in West Africa, according to different studies; before smallpox was eradicated, its death rate was about 30 percent.
Studies have shown that outbreaks of monkeypox tend to die out in humans as the virus passes through successive waves, or generations, of cases. This contrasts with smallpox, which continues to spread for centuries until the person-to-person chain of transmission is broken.
The sudden appearance of monkeypox in the United States is a surprise, representing the latest in a series of emerging diseases to reach this country. A prime example is the mosquito-borne West Nile fever, which has spread through the country since it first entered the Americas in 1999.
Precisely how monkeypox reached the United States is unknown. Dr. Ostroff said that the disease agency was investigating possibilities that included the arrival of an infected person or animal from West Africa.
Dr. Kurt Reed, an infectious-disease pathologist who runs the microbiology laboratory and the clinical research center at the Marshfield Clinic in central Wisconsin, said his laboratory had detected the virus in specimens from a 4-year-old girl who had been bitten on the finger by her new pet prairie dog in mid-May.
The girl's parents, who also had contact with the prairie dog, later developed the disease, though the 38-year-old father, who had been vaccinated against smallpox as a child, had a milder case. The monkeypox virus was also detected in a lymph node from the prairie dog, which died a few days later.
The girl went to the clinic with a lesion on her finger, Dr. Reed said, and bacterial cultures quickly ruled out tularemia and the plague. Biopsies of lesions taken from the girl's mother showed a poxlike virus. Cultures from the mother's virus and from the prairie dog matched and suggested an ailment from the orthopox family, Dr. Reed said.
"Right then we knew we had something interesting," he said. "We do lots and lots of virus cultures. This was very unusual. There's nothing really in the literature about prairie dogs having pox viruses."
When the clinic contacted the state health department, the doctors were told of similar cases in the Milwaukee area and learned that the prairie dogs may have been housed with Gambian rats through an exotic pet dealer in suburban Chicago. "That really raised the suspicion that this was an old-world virus that had made its way into the United States," Dr. Reed said.
The disease agency said that the prairie dogs were sold by a Milwaukee animal distributor in May to two pet shops in the Milwaukee area and during a pet "swap meet" in northern Wisconsin. The Milwaukee animal distributor obtained prairie dogs and a Gambian giant rat, which was ill at the time, from a northern Illinois animal distributor. Investigations are under way to trace the source of the animals and to find out where they went, Centers for Disease Control officials said.
Preliminary information suggests that animals from this distributor may have been sold in other states, which the agency did not name.
Prairie dogs and Gambian rats are part of a wide array of exotic animals feeding a growing and diversifying niche pet market, though some animal rights advocates oppose their domestication.
Prairie dogs, plant-eating members of the squirrel family, are believed to have a sophisticated communication system through smell and touch, and they are known to burrow complex tunnel systems.
The rats, which grow to the size of small cats, eat pet food as well as fruits, vegetables and cooked meats.
"They are intelligent, social and can be very gentle if handled from an early age," one enthusiast, Jazmyn Concolor, posted on the Web site www.altpet.net, adding that one rat sleeps with a stuffed toy lion. "They are not pets for everyone, requiring patience and understanding of their habits."
The disease centers urged people to avoid contact with prairie dogs and Gambian rats that have missing patches of fur, rashes or discharges from their eyes or nose, all signs of the illness.
The agency also urged people to wash their hands with soap and water after contact with any animal and to warn doctors and hospitals in advance in seeking medical care if they thought they might be infected.
The disease agency
issued no specific treatment recommendations, but scientists are testing an
antiviral drug, cidofovir, for its efficacy (New York Times, 2003).
Title: Rift Valley Fever Virus Infection Among French Troops In Chad
Date: June 9, 2003
Abstract: During the rainy season every year, outbreaks of self-limiting nonmalarious febrile syndromes have occurred in French military troops on duty in Chad. To determine the cause of these syndromes, the Tropical Medicine Institute of the French Army Medical Corps implemented an arbovirus surveillance program in Marseille.
During summer 2001, we collected samples from 50 soldiers who had a febrile illness. All blood spot samples tested negative by enzyme-linked immunosorbent assay (ELISA) for certain antigens (i.e., dengue virus, West Nile virus, Chikungunya virus, and Wesselsbron virus). However, after co-culture of 31 peripheral blood lymphocyte samples with C6/36 and Vero cell lines collected in NDjamena, Chad, in August to September 2001, two strains of Rift Valley fever virus (RVFV) were isolated and identified by using indirect immunofluorescence with a specific mouse ascitic fluid and by using reverse transcriptase-polymerase chain reaction (RT-PCR) and sequencing. In retrospective testing, we found that all serum specimens tested by ELISA for RVFV-specific immunoglobulin (Ig) M and IgG were negative. The second serum samples from the two case-patients with these strains, collected 2 months later, were strongly positive (IgM 1/200,000; IgG 1/5,000).
Rift Valley fever, a febrile disease that affects livestock and humans, is transmitted by mosquitoes and caused by a virus (genus: Phlebovirus, family: Bunyaviridae) that can persist in nature in contaminated eggs. The virus was first isolated in Kenya in 1930 and is endemic in the region. In Chad, the disease was first reported in 1967 at the same time as in Cameroon; no strain was isolated at that time. Since 1977, RVFV infection resulted in 600 deaths in Egypt, 300 in Mauritania in 1987, and 200 in Saudi Arabia and Yemen in 2000 to 2001.
To characterize these RVFV strains, parts of the three genome segments (L, M, and S) were amplified by using RT-PCR and sequenced as described. The figure shows the phylogenic tree constructed from the sequence of the region coding for NSs in the S segment, by using the neighbor-joining method implemented in Clustal W (version 1.6; available from: URL: http://www-igbmc.u-strasbg.fr/BioInfo/ClustalW/clustalw.html). The two strains identified in Chad are quite similar. They are located within the East/Central lineage established previously, which contains the virus that circulated in Madagascar (1991), Kenya (1997–1998), and Yemen and Saudi Arabia (2000–2001). Sequencing of the region in the M and L segments led to the same clustering (not shown), suggesting that this virus did not evolve by reassortment. Determining the origin of the virus is difficult, but its genetic properties suggest that this strain has a Kenyan origin. Before this isolation, no RVFV strains from Chad had been genetically characterized.
This strain may be endemic in this region of Central Africa, or the RVFV strain circulating in the Eastern countries may have been transported outside of the territory (which was likely the case in Yemen and Saudi Arabia in 2000). Of the two case-patients, one soldier did not leave NDjamena during his 3-month tour of duty, whereas the other had been in contact with livestock in a flooded area before onset of symptoms. Contamination may have occurred through infected animals or mosquitoes, although sheep living in the area did not show any sign of disease (i.e., spontaneous abortions, deaths). The two cases we describe were self-limiting; however, deaths from this illness have been reported in nonepidemic settings in Central African Republic. Our data emphasize that healthcare providers should systematically consider Rift Valley fever as a diagnosis for febrile syndromes in persons returning from Africa, even in nonepidemic settings (CDC, 2003).
Date: June 11, 2002
Abstract: Federal health officials are expected to announce today that smallpox vaccinations will be made available to certain people who have been exposed to prairie dogs and other animals infected with monkeypox in recent days.
Smallpox vaccine is considered the most dangerous of human immunizations, but it can protect against monkeypox.
The Centers for Disease Control and Prevention is expected to make the vaccinations available as an option to highly selected groups like health workers who care for patients with monkeypox, people who have been exposed to animals sick with monkeypox, veterinarians who care for animals suspected of having it and scientists investigating monkeypox.
The investigation of human monkeypox cases expanded to a fourth state, northern New Jersey, yesterday as the number of suspected monkeypox cases rose to 50: 23 in Indiana, 20 in Wisconsin, 6 in Illinois and 1 in New Jersey. No one has died.
The total is more than double the 23 cases reported in three states when the disease centers urgently announced the outbreak over the weekend. The increase in cases under investigation has resulted largely from widespread publicity that led people to report rashes and illness to health officials, officials of the centers in Atlanta said.
The monkeypox cases are the first detected in the Americas. Most suspected cases had direct contact with prairie dogs or at work in veterinarian offices and pet shops.
Monkeypox patients typically fall ill with signs and symptoms like fever, headaches, dry cough, swollen lymph nodes, chills and drenching sweats.
One to 10 days later, patients develop rashes consisting of blisterlike pimples that filled with pus, broke open and produced scabs.
The rash often erupts in different stages, or crops, as it appeared on the head, trunk and arms and legs.
The Centers for Disease Control and Prevention is also expected today to announce a definition of human monkeypox, which would be critical in determining who would be eligible for smallpox vaccinations as well as investigating the outbreak.
United States officials stopped routine smallpox vaccinations in 1970, about a decade before eradication of smallpox from the world.
On Monday, a subgroup of a national panel of immunization experts appointed by the Centers for Disease Control and Prevention to serve on its Advisory Committee on Immunization Practices began discussions on whether and how the smallpox vaccine might be used.
Discussions focused on the benefits and risks of smallpox vaccine for monkeypox, a viral disease that can be fatal in 10 percent of human cases. The death rate for smallpox was about 30 percent.
But smallpox vaccination can also be fatal. Studies from the 1960's, when smallpox vaccinations were routine, found that for every million people older than 1 year old who were vaccinated, 1 or 2 died, 9 suffered from brain infection and more than 100 developed eczema vaccinatum, a severe illness and skin rash that can leave deep scars and can occasionally be life-threatening.
The government owns all the smallpox vaccine in the United States. This year, the government began offering it to health care workers to protect against any cases that might result from an attack in which terrorists released the virus.
The only known stocks of smallpox virus are kept at the Centers for Disease Control and Prevention and in Russia, both with the approval of the World Health Organization.
But the Bush administration has warned that Iraq as well as other countries and rogue groups might have obtained smallpox virus from the official stores in Russia and begun a program to vaccinate health care workers before the war began against Iraq.
The number of people for whom smallpox vaccine might be offered to protect against monkeypox would be small, the panel's chairman, Dr. John F. Modlin, said in an interview before the panel's meeting (UCLA, 2003).
Title: Death Sought For Animals In Monkeypox Case
Date: July 3, 2003
Source: New York Times
Abstract: Moving to prevent monkeypox from reaching wild animals in the United States, the Centers for Disease Control and Prevention recommended yesterday that all 850 animals from a contaminated shipment of exotic pets from Africa in April be destroyed, along with all prairie dogs that might have been exposed to them.
The agency warned pet owners not to release any sick or potentially exposed animals into the wild.
Other mammals in homes or pet shops that might have been exposed should be killed or should be quarantined for six weeks and watched for symptoms — fever or cough, cloudy or crusty eyes, swollen lymph nodes or rash, the agency said. Bodies should be burned, not buried or thrown out, and the premises disinfected, it added.
An outbreak of monkeypox tentatively traced to a Gambian giant pouched rat in the shipment has caused 81 confirmed or suspected cases in humans, mostly in the Midwest. Its spread seems to have stopped, and no cases of human-to-human transmission were found. But the disease spreads easily to rodents.
A spokesman for the agency acknowledged that the authorities did not know the whereabouts of many of the estimated 850 animals in an April 9 shipment from Ghana to Texas, nor do they know if any were released.
"That's one of the things we're really worried about," said David Daigle, a spokesman for the agency. "Tracking them all down is darn near impossible."
Nonetheless, a "very aggressive" effort is on now, said Dr. Martin Cetron, the agency's deputy director for quarantine. But many were sold at informal pet swaps, he said, "and then things end without a good paper trail."
Monkeypox — so called because it was first diagnosed in monkeys — is a less virulent cousin of smallpox, and vaccination against smallpox appears to protect against it. There were no deaths in the June outbreak, but in West Africa, up to 10 percent of cases are fatal.
At the beginning of the outbreak, the centers and the Food and Drug Administration banned importing of all African rodents and the sale or distribution of six species from the April shipment: tree squirrels, rope squirrels, dormice, Gambian giant pouched rats, brush-tailed porcupines and striped mice. They also banned the transport, sale or release of prairie dogs.
Yesterday's directive was ambiguous about what constituted contact with an infected animal, and it confused some pet shop owners. Details of the directive are at cdc.gov/ncidod/monkeypox /quarantineremoval.htm.
Eileen Whitmarsh, an owner of Rainbow Pets in Shorewood, Wis., who caught monkeypox from a prairie dog in her store, mistakenly thought the order meant she had to kill the 60 apparently healthy hamsters, rats and gerbils she now has quarantined.
"Our animals are checked by the Health Department daily, and they are having babies," Ms. Whitmarsh said. "Sick animals do not have babies."
David Crawford of Boulder, Colo., acting director of the Prairie Dog Coalition, which defends wild prairie dog habitats and opposes keeping the animals as pets, called the euthanasia suggestion "a classic case of blaming the victim."
"This problem was caused by human beings, and it's easy for us to take the `kill them all' approach," he said. "But if this was a human population, we'd be aghast at an order to kill. This calls for quarantine and testing, not euthanasia."
Two weeks ago, at a meeting of the Advisory Committee on Immunization Practices at the centers, Dr. Gregory A. Poland, a committee member and the chief of vaccine research at the Mayo Clinic in Minnesota, asked why the agency had not already ordered all possibly exposed animals killed.
An official of the centers replied that people became attached to their pets.
"So what?" Dr. Poland said. "I know what we'd do if this was an outbreak of mad cow disease. We'd kill the whole herd" (New York Times, 2003).