The pneumonic form, which spreads like the flu, has a much higher fatality rate close to percent and works faster than its bubonic cousin, killing its human host within a few days if left untreated. The condition most commonly associated with the plague is, of course, the buboes: swollen lymph nodes that have been described throughout history as kernels, pimples, wheals, and biles. In , during the Third Pandemic, Alexandre Yersin, a French physician and bacteriologist, determined that the plague was caused by the previously unknown bacillus pestis.
As is common in scientific practice, the bacterium was later named in his honor: Yersinia pestis. Infographic: A Recent History of the Plague. Click to enlarge. Before my trip to Madagascar, I assumed the bare and chilling facts of the disease would allow the story to write itself. When I spoke with friends and colleagues about the story, I would get one of two contradictory responses—confusion as to what the big deal was it only kills a few thousand people a year. How bad is it, really?
They know it just takes a perfect storm of filth, fleas, garbage, rats, and diminished immune systems to set off an epidemic that could potentially make it off the island and spread to the African coast. Something about Madagascar has made it the most vulnerable country on the planet for a serious outbreak at this moment. I wanted to know what that something was. Rasoa Marozafy and his wife, Veloraza, who both contracted plague in the fall of Some 88 million years ago the island broke away from the supercontinent of Gondwana, eventually being pushed miles off the coast of Mozambique.
It is one of the rare places on earth that has preserved its own unique ecosystem. The country is populated by dark-skinned inhabitants, descendants of ancient Indonesians who arrived on the island around the ninth century, having sailed nearly 5, miles across the Indian Ocean in elegant outrigger canoes. At the turn of the 20th century, France unified the island under a single regime.
The first recorded instances of the plague followed soon after, worming its way aboard merchant ships and into the port city of Toamasina. By , the disease had become endemic in the rodents and small mammals of the Highlands. Since then, the plague has flared up here and there, mainly as a rural phenomenon with occasional urban epidemics.
The plague is almost impossible to eradicate from Madagascar, thanks to a complex interaction of natural and sociocultural factors. According to a report by the US National Library of Medicine, the high percentage of animals carrying the disease lays the foundation for transmission, and social and economic conditions further encourage the periodic leap to humans. Outbreaks of the plague in Madagascar usually occur in villages above an altitude of 2, feet and can be linked to the activities of farmers.
The agricultural infrastructure of the Highlands provides three distinct habitats for the plague to thrive: hilltop houses, hedges planted around livestock enclosures, and the irrigated rice fields of lower-lying areas. Food shortages and farming can serve as triggers that cause the rat population to drop significantly while, inversely, fleas flourish. Without the rats as a primary food source, fleas are forced to look for other mammals—such as humans—to serve as hosts.
In northern Madagascar, the plague spikes between October and April, when the warm rainy season ensures that the temperature rarely drops below 70 degrees. The sustained humidity acts as an incubator for Xenopsylla cheopis , better known as the Oriental rat flea, the primary vessel for the plague.
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Compounding the difficulty of controlling the flea population during the rainy season, new research by the US National Library of Medicine suggests that the plague bacterium can quite literally persist underground between outbreaks via rats that infect themselves by burrowing into contaminated soil. While research is still in the preliminary stages, it has been demonstrated that Y. While vermin are the natural scapegoat for the plague, humans are the true culprits.
In villages, crops are often stored inside houses to prevent robbery, attracting rats and fleas. Deforestation by illegal loggers, a timeless but growing problem in Madagascar, forces rats from the forests and into the villages. From there, impoverished living conditions and migrants fleeing those conditions can quickly result in outbreaks in previously uninfected communities.
Even more chilling, traditional Malagasy funereal practices help to ensure that the plague can continue to spread even after the victims have been buried. Despite these considerations, and evidence that instances of the plague may be increasing, the Malagasy government stopped tracking metrics on the plague in , due to financial constraints.
Evolving out of the Bacteriological Institute established by the French colonial government at the turn of the 20th century, throughout its various iterations the Institut Pasteur has long been crucial to the tracking of communicable diseases in the country.
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A visit there was crucial if I hoped to understand just how bad things could get. He then cut open its carcass with a scalpel and scissors, using tweezers to extract its liver from a tightly packed coil of organs. Some of the technicians instinctively backed away, raising their hands in morbid respect for the potential devastation this tiny flea was capable of causing. I asked Michel whether it was plausible that this particular Oriental rat flea carried the plague.
As the only official group dedicated to fighting the plague in Madagascar, they have quite possibly the worst job in the country. Their days consist of traveling to remote, at-risk areas where the primary objective is to catch potentially infected rats and perform autopsies on them to search for signs of the highly virulent disease. Within hours I found myself crawling on my hands and knees through the undergrowth around Antananarivo, hunting for rats that may or may not have been infected with one of the most devastating diseases known to man. Our field gear consisted of a pen and paper for note taking, sliced tilapia for bait, and two-door rattraps made from rust-resistant mesh cages that the team hides in the undergrowth, where they are left out overnight.
With any luck, there would be live rats trapped inside when we checked the following morning. Everyone I spoke to in Madagascar had heard of and expressed concern about the plague.
I sensed an underlying fear that, if the disease were to reach the capital, the results would be catastrophic, as crowding could cause it to spread far more rapidly than in the countryside. Christophe Rogier, a cheerful man with a thick French accent and a close-cropped buzz cut who serves as the director of the Institut Pasteur. The disease is dangerous for the population. There are more rats in the city than in rural areas. The rats are in closer contact with the population, and the houses are overcrowded, so we can imagine that the spread of the plague from human to human would be faster in the cities than it would be in the country.
The slums of Antananarivo share many characteristics with the densely populated medieval cities that were virtually wiped out in the mid s. As the city grew and developed, it sprawled down the mountains and into their low-lying valleys. As real estate on the mountain became increasingly scarce, the hillside communities became slums and have continued to grow unabated.
An outbreak of the plague here would be catastrophic to the local population. Just as they have for centuries, the men and women of Antananarivo walk barefoot through the streets, which are little more than mud ruts lined with open sewer systems clogged with trash and human waste.
The latticework of canals that crisscrosses the city is also backed up with garbage. I watched as small bands of children waded and swam through the fetid sludge, hunting for anything worth selling that might be floating in the muck. The day after I returned from the Highlands, I was given a private tour of one of the worst-off slums in the city by a year-old security guard and father of three named Andriambeloson Solofo Pierre, who goes by Billo.
Like most people in Madagascar, he and his family cannot afford any real form of health care. He pointed to a group of children playing in the viscous water.
When the French colonized the region in , they set to work stripping the area of its resources and slaying more than , Malagasy who fought against the exploitation of their land. After a monitored independence was initiated in , the country quickly devolved from the hope of autonomous democracy into total anarchy, and after that a failed Marxist utopia. This all changed when President Marc Ravalomanana was voted into office in But this political and economic optimism was short-lived. In , the Ravalomanana government was ousted in a bloody and, many Malagasy believe, French-backed coup, led by a former DJ and media entrepreneur named Andry Rajoelina, who at the time was serving as the mayor of Antananarivo.
He immediately set up the so-called Fourth Republic and dubbed himself president of a fantasy regime called the High Transitional Authority. The country was suspended from the African Union, and according to a report by the Organization for Economic Cooperation and Development, it was the most under-aided country on the planet.
These cuts affected virtually every facet of the Malagasy economy and evaporated the fragile middle class. Jean-Louis Robinson, the former minister of health who was ousted by the coup. We spoke at his compound, a lavishly decorated home overlooking a cluster of urban farms. A stout man with darting eyes and a hairpiece, Robinson told me that after Rajoelina took power, more than health-care centers were closed across the country. Public restrooms are insufficient; garbage is not picked up regularly.
On December 20, , following a series of political debacles surrounding the presidential election, Rajoelina and his High Transitional Authority lost control of the presidency to his former finance minister, Hery Rajaonarimampianina. Almost immediately, the US Department of State lifted all remaining restrictions on aid to Madagascar. For his part, Billo told me, all he can do is wait for the next plague season, which begins in October. As we wandered through the throngs of bodies crowding the streets of Andavamamba, he wondered aloud about the chances of the plague reaching the capital—and how many might perish if it did.
An avidin-biotin-peroxidase complex method has been used successfully for demonstrating SV antigen in histologic sections Hall and Ward, Isolation of SV may be achieved using BHK or primary monkey kidney cell cultures, or 8 to 10 day embryonated hen's eggs inoculated into the amniotic or allantoic sac Parker and Richter, The mouse antibody production MAP test may be used in testing transplantable tumors and other biologic materials for contamination by SV Rowe et al.
Ordinarily, exclusion requires very strict adherence to systematic measures for preventing entrance of the infection into an entire facility or institution. SV free subpopulations of rodents must be identified by regular health surveillance of a supplier, transported to the user facility in containers which prevent contamination. In addition, all biological materials such as transplantable tumors coming into the institution must be pre-tested and shown to be free of the virus before experimental use Collins and Parker, ; Parker and Richter, Once infection has been diagnosed in a facility, prompt elimination of infected subpopulation s is essential to prevent spread of the infection to other rodents on the premises.
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A less effective alternative is to place the infected animals under strict quarantine, remove all young and pregnant females, suspend all breeding, and prevent addition of other susceptible animals for a period of weeks until the infection has run its course and the virus has been eliminated naturally.
Because of this alternative, cesarean derivation of infected stocks usually is not justified.
Vaccination may prove useful in some situations Parker, ; Eaton et al. A number of killed vaccines Fukumi and Takeuchi, ; Nedrud et al. Experimental infection of mice with SV decreases pulmonary bacterial clearance Degre and Glasgow, ; Degre and Solberg, , probably through a variety of mechanisms including altered phagocytic function. Altered functions in pulmonary macrophages that have been identified include: decreased Fc receptor and non-Fc receptor mediated attachment, decreased Fc receptor and non-Fc receptor mediated ingestion, inhibited phagosome-lysosome fusion, decreased intracellular killing, decreased degradation of ingested bacteria, and decreased lysosomal enzyme content Jakab, ; Jakab and Warr, Concurrent SV and M.
SV infected mice have been reported to have deficiencies in T and B cell function that persist throughout life Kay, , ; Kay et al. Unfortunately, these results have not been confirmed by other investigators.
SV infection transiently increased splenic IgM and IgG plaque forming cell responses to sheep red blood cells in mice Brownstein and Weir, SV infection inhibited in vitro mitogenesis of lymphocytes Wainberg and Israel, ; Roberts, In rats, infection altered the mitogenic responses of T cells, reduced severity of adjuvant arthritis, and decreased antibody response to sheep erythrocytes Garlinghouse and Van Hoosier, Mice naturally infected with SV have been found to have increased natural killer cell mediated cytotoxicity Clark et al.
SV infection altered host responses to transplantable tumors Wheelock, , ; Collins and Parker, ; Matsuya et al.