Week 5: Yellow Fever + Dengue Case Studies, Plague

What do you know about the location and identification of Gibraltar?

-It is located at the southern tip of Spain where the Mediterranean Sea and Atlantic Ocean are closest

-it's primarily a fortified Garrison post under British rule since 1704. In 1830 it was recognized as a British colony and it is now considered British overseas territory

what do you know about the social status based on where you live in Gibraltar?

-Gibraltar is a very mountainous place. The higher you lived up on the mountain and stones, the cheaper the housing was and therefore the lower you were on the mount and chances are the more money and the higher social status you had. Its land and the way it is built also made food growing near impossible and so they had to get food from other places

what do you know about gibraltarians?

-They are a fusion of European North African and Mediterranean people

-in the 19th century they were a motley population including seedy adventurers and fortune hunters. It may have a weird landscape but it was Navy and so it had docks and ports and was seen as a place having potential. There was a lot of jobs related to ships available. It also had a large religious diversity such as Jewish people who played a very important role in the movement of foods due to Morocco connections

what are some of the important aspects to Gibraltar in terms of why it's desired and jobs but also things that enhance introduction and transmission of disease?

-Commercial centre common naval port and Garrison as well as a coaling station brought in a lot of immigration through available jobs as well as trading opportunities however this also increased the flow of people and goods which could bring and transmit diseases

what do you know about Gibraltar in terms of how it got yellow fever in 1804?

-There was a history of yellow fever epidemics in nearby Spain. It is important to note that this disease was not endemic in Spain because it came from Cuban mosquitoes coming on ships from Cuba which gave sugar etc. It was periodically reintroduced

-epidemics in Spain did not mean epidemics were going to happen in Gibraltar however in 1804, Gibraltar got a yellow fever epidemic pretty bad with 5733 deaths

what do you know about Gibraltar in terms of how yellow fever spread once it arrived in 1804?

-It is thought that it first occurred in a residential block called boyd's buildings where a shoe keeper named Santo fell ill first period him and others were probably in Spain an rushed home to Gibraltar before the borders closed once it was announced that Spain was experiencing an increasing number of yellow fever cases. When they arrived home to Gibraltar they probably brought it with them. It is important that this is not enough to cause an entire Gibraltar epidemic. Vectors were also present and the fact that your brother had the whole population of susceptible people also led to this outbreak

Travel and trade routes connect to the movement of vectors and viruses. What is an example of this in terms of Africa and the Americas?

-Linkage between Africa and Americas in colonial slave trade. Many African people were brought to the Americas on boats unwillingly. Mosquitoes from Africa probably came on these ships with them which brought them to America. These mosquitoes can tolerate brackish water but cannot tolerate high salt concentrations so they probably lived on and around water supplies on the ship since they could not drink the ocean water. The virus was probably first established in sylvatic cycles with indigenous forest mosquitoes such as genus Haemagogus. It then would have found its way into other domestic mosquito populations

Uncontrolled immigration that increase the presence of diseases led to committee for preservation of public health. What are some of the things that they did or did not implement?

-They led to reform such as fox generalizations- in example was reforms on immigration policy's; Gibraltar intended to be the jewel in england's crown but it could quickly become her greatest curse with its high immigration rates so these policies restricted immigration to a great extent

-communities wanted to avoid quarantine because economic repercussions and some didn't believe the disease was caused from outside forces or people coming in

when the yellow fever outbreak occurred in Gibraltar in 1804, it was the Jewish community that became scapegoated. Why?

-As we have mentioned before, the group of people that escape coded is usually scapegoated due to already underlying worries or discriminatory aspects against them before anything occurs. Before the 1804 yellow fever epidemic, there was worried that the Jewish communities key connections to the movement of food made the Jewish community too powerful

what did the Lieutenant governor George Don enact in 1828 that people did not want to do before?

-He enacted quarantine period he put limitations on ships. They had to wait a certain amount of time before movement of goods

what do you know about fever passes?

-In 1828, Juan Peña, 17 year old Catholic ,was granted a fever pass. People started to recognize and see the significance of acquired immunity. They understood people who had yellow fever and lived were now immune to a sense and thus they got this pass if they had a fever it was not assumed that they had yellow fever

Note: Relatively speaking, 1804 epidemic was particularly devastating. Out of the about 5000 deaths, most were civilian relative to military probably due to an increase in immunity in the military populations due to excessive travel and being exposed to other things

what do you know about population pyramids?

-They are based on the collection of information from census is. They often divide the population into male and female and have age on the Y axis with percent of inhabitants on the X axis

-specifically in regards to the 1804 yellow fever, you can see on the population pyramid for that there was a drastic decrease in percent of inhabitants due to the deaths

although many people in Gibraltar tried various things to end the epidemic. What ended up being the thing that slowed it down or ended it temporarily?

-Temperature. If the temperature dropped below 15 degrees Celsius, the mosquitoes became more disturbed and disoriented and thus they were not able to transmit the illness as effectively and the case is drastically reduced. Some referred to this as waiting for the frost because they knew once it got cold, yellow fever would slowly disappear

we are now going to look at dengue fever in 21st century Dhaka Bangladesh. Whose thesis are we going to base this on an what do you know about the general population size of Dhaka?

-We're going to base this on Afroza sultana masters thesis in anthropology at the University of Manitoba. This was written in 2014. "8 to 10 years ago, dengue fever was a killer disease... but it is not a killer disease anymore": a qualitative approach to dengue in Dhaka Bangladesh

-Dhaka is a megacity with 14 million people. It is special because it is in a developing country which does lead to order issues such as health having enough room governments not being run properly etc

-every year 300,400 thousand of bangladesh's urban poor relocate to Dhaka due to better employment and wages. As a result there is a massive rate of unplanned urbanization

what are some examples of other megacities?

-In total there are 28 in the world. Summer New York, London, Tokyo, Shanghai

what do you know about a few tragedies in Dhaka Bangladesh?

-The collapse of the Rana Plaza on April 24th 2013. 11129 deaths and 25115 were injured. This was one of the worst industrial accidents ever

-name tally disaster in old Dhaka in 2010- 124 people died. A massive fire broke out in a portion of old dahka however do too overcrowding and infrastructure there were major problems with fire trucks being able to access the building and there was major issues in people being able to escape the building

-there are also things called shanty towns which are separate towns of people some have more infrastructure than others. Usually have to use a boat to get there. These aren't necessarily tragedies but they do showcase the vast difference in way of living

what do you know about a problem in Bangladesh in relation to water supply and what is the response to it and the recommendation?

-the problem: lack of a reliable water supply, even piped water access relies on electricity

-the response: to store water however this means there's a risk for disease because stored water means there's an opportunity for Aedes aegypti, a vector of a number of diseases, including dengue fever

-recommendation: to make stored water more safe such as by covering it

what do you know about a problem in Dhaka Bangladesh in relation to risks of dengue and what were some themes that were present because of it?

-The problem: underestimating the risk of dengue

-themes: contextualising dengue: daily stressors, other struggles that people were facing, were overshadowing dengue fever. people often think of dengue as a past disease that they don't need to worry about anymore. Dengue and the language of virus vor which refers to a common fever- one that with or without medicine will be cured within seven days. there was also a theme of people not recognizing the difference between dengue fever and dengue hemorrhagic fever -People also often assume that if they survived it they were fine however when you got it the second time you often got the worse one

Regarding the bubonic plague. What is it also known as and why did people talk about it in reference to delicate balance?

-It is also known as the Black Death

-bubonic plague, like any other play, involves delicate balance- the fact that key parts of the puzzle must be in place for an epidemic to even occur such as microbes reservoirs and hosts and vectors

what do you know about who discovered and when they discovered the bacterium that causes plagues? What do you know about the bacterium in general?

-Yersina pestis was isolated by Alexandre Yersin in 1894

-DNA sequencing suggests that the bacterium involved overtime with various gains and losses of DNA but only seemed to become lethal about 1500 years ago. Previous to this it was just a gastrointestinal bug

-evidence suggests that the bacterium arose in Asia. It spread and is likely been present for the last 2000 years in various places such as parts of Africa

what are the two epidemiological settings for plagues and what do you know about these?

-Sylvatic, wild, played: typically circulates among rodents resistant to the infection- tolerant of plague bacterium

-urban, domestic, plague: humans and commensal rodents

-vectorborne transmission such as fleas

what are some resistant rodents that we talked about in relation to plagues?

-Some resistant rodents who are important reservoir hosts of plague bacillus and animal populations are voles which are field mice as well as deer mice

what are incidental hosts?

-There are other wildlife that can become infected through reservoir hosts such as rabbits and squirrels and Prairie dogs which are referred to as ground squirrels

rat borne epidemics account for many human plague epidemics. What do you know about some of the specific rats we need to be concerned about in relation to human epidemics of plagues?

-Rattus rattus which is black rats and ship rats and roof rats

-These are found throughout the world as human commensal but both domestic and sylvatic ecosystems also have them crossing through which makes control difficult and spread of diseases very easy

-These rats are probably native to Asia but have an especially wide distribution now. They are high producers that breed all year producing three to five litters per year with an average of 6 to 10 rats per litter

what do analysis suggest about how plague entered North America and when this occurred?

-Plague entered North America in about 1900: at the West Coast in port cities from rat infested ships. The rats on these ships then spread throughout North America and infected incidental hosts such as Prairie dogs

-the last known rat borne epidemic in North America was in LA in 1924 to 1925. Currently North America has sporadic outbreaks from contacts with rodent reservoirs and incidental hosts

what do you know about how the plague spread past the Rocky Mountains?

-Farmers in land became very interested in the epidemic of disease and high mortality of Prairie dogs. Prairie dogs made farming very difficult as they often dug up a lot of things and messed with the crops. So when farmers notice that Prairie dog populations were dying on the other side of the plane, they collected sick Prairie dogs and introduce them into the inland population on the other side of the Rocky Mountains in hopes that they would infect the already present Prairie dog population and kill it off

In cases of bubonic plague, what are the three most important vectors to consider and what do you know about them?

-Xenopsylla cheopis (fleas for black rats); Historically important

-Pulex irritans (fleas for humans and farm animals); less common today

-Oropsylla montana (fleas for squirrels and Prairie dogs); most important vector in the USA today

NOTE: male and female fleas take blood meals. This is very different than the flies we talked earlier in this class where the females only take blood meals to help with reproductive success

what do you know about the fate of the flea in relation to Gage and Kosoy 2005?

-"[Bacot and Martin, 1914] Found that after X.cheopis feeds on an infected rat, the ingested plague bacteria multiply rapidly in the fleas midgut and spine filled proventriculus and form noticeable colonies in just a few days. As these colonies grow and coalesce, they eventually become enough to occlude the proventriculus, affectively blocking the movement of blood from the foregut to the midgut, causing the flea to starve. Blocked and starving fleas repeatedly attempt to feed by using their pharyngeal muscles to draw blood into the forgot, which causes distention of the esophagus but no movement of blood past the proventricular block. eventually the flea is forced to relax its pharyngeal muscles, which results in Y.pestis Contaminated blood being pushed from the distended esophagus back into the feeding site, thereby causing infection of the vertebrate host."

what are the characteristic bubonic plague symptoms?

-Hemorrhaging under the skin which causes skin darkness due to blood

-swollen, tender, painful lymph nodes called bubos

what do you know about lymph vessels and nodes in the body?

-They are all throughout the body but there are large clusters of them in the neck armpit and groin

-critical part of immune system

-lymph vessels carry foreign or unhealthy matter back to the node for processing period lymph nodes enlarge attempting to destroy this matter. They are sites of learning for the immune system

what are the three plague etiology that we looked at and what you know about them?

-Bubonic plague which affects the lymph nodes. If left untreated it can enter the bloodstream and travel to the lungs

-septicemic plague which infects the blood streams and organs. After the lymph nodes, or breaks in skin and direct contact with plague infected animal such as skinning

-pneumonic plague which affects the lungs; Inhaled, cough, difficulty breathing, bloody sputum

Which country has the highest incidence of plague cases worldwide and what do you know about it?

-Madagascar has the highest incidence of plague cases worldwide and suffered its worst outbreak in over 50 years between August and November 2017, with 2348 cases and 202 deaths

-The cases are increasing due to climate change and environmental degradation

What causes plagues?

-Yersinia pestis

Why slash how did medical semiotics emerge?

-Ginzburg 1989 explains that medical semiotics emerged as epistemic paradigm in the late 19th century. It offered a method of constructing reality through decipherment and sequencing of superficial, often very subtle, clues

what does zoonotic semiotics call attention to?

-It calls attention to different bodies affected by plague and implicated in its transmission. What are they? How did they interact? Why do they interact

what is the context of the Madagascar outbreak of plague in the article?

-the population mainly consists of Bezanozano and Betsimisaraka, whereas small city of Mira mango also includes Merina- politically dominant population of central Highlands

-Over the course of 10 days in August of 2015, 14 people were infected and ten died, eight of which were kin

-this was a minor outbreak but it still needed to be determined how it happened. Dr Beza Ramasindrazana, a mammologist and ecologist with pasture institute and the lead author of the article, collected 100 rats from plague zone over course of three days and analyzed their spleens: 22 tested positive for the antigen. She traced the first case to even affection buyer at and then from person to person

What do you know about the treatment of plagues?

-If disease is not treated early with the course of Cotrim which is a combination of sulfamethoxazole and trimethoprim, bacteria can invade the lungs. Without injections of streptomycin, one dies within 24 to 48 hours

In general what is the difference between the symptoms of bubonic plague and pneumonic plague?

-In general, bubonic plague victims experienced painful lymphatic swelling, or bubos in groin armpit neck, as well as a fever body aches listlessness an acute headaches

-pneumonic plague victims suffer a sudden bout of fever, body aches, chest pains, and chills. Rapidly escalates to bloody diarrhea, profusion of sputum, and vomiting blood

what was weird about the 2015 outbreak of plague in terms of symptoms?

-Interviewers could only recall symptoms of pneumonic plague, an implicit eraser of rats role in disease transmission

-the author of the article thus seeks to view rats as Co participants rather than vessels of disease

how did the plague arrive in Madagascar?

-In 1998 it arrived indirectly. The government general Maréchal Galliéni Wrote a letter to the minister of colonies in Paris that explained a passenger steamship, La Gironde, was en route to Mozambique from Madagascar when it came into contact on open sea with a ship of British East India company where they must have picked up the plague and brought it home with them

-by February of 1899, officials had recorded 285 cases and 195 deaths. In July, the plague broke out in Tamatave again but with fewer cases. Officials contributed this to hygiene measures implemented in the wake of the first outbreak

After the first outbreak of plague in Madagascar, what was put in place to hopefully decrease the spread?

-After the first outbreak and with increasing vigilance, the state regulated burial and band examination of plague victims. Famadihana was a ritual that typically involved re earthing passed away family members and performing a ceremony, in a way to connect them to the spirits but this was banned if the person had died from the plague

What do you know about frank G clemow's?

-He was a British doctor of public health who did work on plague in the lower animals. He discovered plague stricken rats usually leave their underground habitations and migrate, often for considerable distance. Rats had bubos, spasmatic and paralytic symptoms, and a dazed appearance and staggering gait just like humans that had the plague did

How could you tell if a rat had died from the plague or unrelated causes?

-rats that died of the plague laid prone on their bellies, with all four limbs extended. Rats that die of natural causes are more usually found lying on one side with limbs flexed

What's a fun fact about rat saliva?

-Rat saliva has a numbing property-this means that they can chew at people's feet while they're sleeping

what happened in March of 2017 that pushed a vast number of rats to word houses near water sources in the Moramanga district?

-in March 2017, hurricane Enawo flooding pushed a vast number of rats out of where they were and closer to the people, even in their homes

What do you know about the grave requirements for playing victims and why these were put in place?

-Ministry of Health mandates that graves for plague victims B12 meters deep and a horizontal space must be dug into the side of the pit like a drawer in which to insert the corpse

-this was to prevent people from being able to come into contact with the bacteria it also was so that rats couldn't dig and find it and get infected and continue to pass it on

Note: the original study about Madagascar plague noted the presence of infected rats but the one done by the author of the article was not so sure about if the role of rats was originally correctly noted

what are some possible reasons why people did not detect zoonotic signs in 2015 in the Madagascar plague outbreak?

-Possibility of rats dying or being injured by dogs cats or poison, and the lack of swollen lymph nodes on human patients. Another important reason was the theory of sorcery that was going around that had emerged during the August outbreak. Many thought that the family who is mainly affected was cursed

-there was also a propensity of poor people to self medicate with insufficient doses of Cotrim which may suppress plagues symptoms without eradicating the bacteria and the possibility of spreading it

What is the major question about the 2015 plague outbreak in Madagascar that is still unanswered?

-Patient zero was infected in April but the outbreak was not until August. In addition patient zero had no bubos on the body and had no plague antigens in the blood however they exhibited all other symptoms of pheumonic plague. How was there such a large time gap in between the first case and the outbreak? How did patient zero exhibit practically all the symptoms but not have the antigens?