tag:blogger.com,1999:blog-3492197469143963742.post5706790351961125739..comments2023-06-13T04:45:22.434-04:00Comments on Infection Landscapes: TyphusMichael Walshhttp://www.blogger.com/profile/05038031388622939797noreply@blogger.comBlogger19125tag:blogger.com,1999:blog-3492197469143963742.post-82878154522351462562016-03-31T16:57:19.896-04:002016-03-31T16:57:19.896-04:00A humid environment is crucial to the survival of ...A humid environment is crucial to the survival of the lice and so there is not a problem of the feces drying out, and lice feces contain only 2% water to begin with, so the R prowazekii can survive up to 100 days. Interestingly, the fact that R prowazekii can survive so long in dry feces, which can also be aerosolized, has put typhus on the list of potential bioterrorism threats. Typhus has been associated with wars and poverty and today there is a record number of refugees in the world. People need to be able to wash and change clothes regularly so I worry that typhus could reappear in some of the refugee camps in Europe and Asia.Anonymoushttps://www.blogger.com/profile/07792996651771706535noreply@blogger.comtag:blogger.com,1999:blog-3492197469143963742.post-85543642737960196112015-11-20T12:12:46.479-05:002015-11-20T12:12:46.479-05:00You make a good point and even though it is known ...You make a good point and even though it is known that scrub typhus occurs in the western Pacific region, northern Australia, and the Indian subcontinent, the incidence of scrub typhus is still largely unknown. Many cases are undiagnosed due to the nonspecific manifestations and the lack of laboratory diagnostic testing in endemic areas. Nonetheless, “one study found that the incidence of scrub typhus in Malaysia was approximately 3% per month, and multiple infections in the same individual are possible because of a lack of cross-immunity among the various strains of its causative organism, Orientia tsutsugamushi”. In the end, questions of why the scrub typhus is endemic to the tsutsugamushi triangle remain unanswered. <br />Works Cited: http://emedicine.medscape.com/article/231374-overview#a6Anonymoushttps://www.blogger.com/profile/10812728419197385223noreply@blogger.comtag:blogger.com,1999:blog-3492197469143963742.post-84197280822982153872015-11-12T10:50:44.943-05:002015-11-12T10:50:44.943-05:00Given the globalization and sheer flow of people t...Given the globalization and sheer flow of people through travel, business, etc, in this day and age, I wonder what has kept scrub typhus to Asia and the South Pacific. The Harvest Mite certainly exists in other parts of the world, such as North America. It seems easy enough for mites infected with O. tsutsugamushi to be carried along luggage and then dispersed to other parts of the world...Anonymoushttps://www.blogger.com/profile/00094818324874815633noreply@blogger.comtag:blogger.com,1999:blog-3492197469143963742.post-39604723828989632232015-10-29T23:49:12.908-04:002015-10-29T23:49:12.908-04:00All three different disease types: epidemic typhus...All three different disease types: epidemic typhus, murine typhus and scrub typhus were thoroughly described in this entry. The epidemic typhus is transmitted when feces is introduced into a bite wound by rubbing the bite wound. Feces is transmitted when the louse are blood feeding from humans. New human host are infected when the louse consumes blood from infected human and then feed on non-infected humans and leave their feces on the skin of its host. Murine typhus involves adult fleas emerging from their cocoon when specific signals are initiated. It is interesting that while flea’s cocoons waits for a signal from a host to fully develop they can survive for months in the cocoon state without feeding. This is a long period to survive without nourishment, especially for a developing organism. Lastly, scrubs typhus occurs where transmission islands are specific to the degree of the landscape. It is unfortunate that workers and military people in communities establishing new settlements in deforested locations and arid regions are more likely at risk. It is interesting that although extreme precision is required for transmission to humans, transmission can be widespread among humans in such settings.<br />CassandraDhttps://www.blogger.com/profile/11409445804775833571noreply@blogger.comtag:blogger.com,1999:blog-3492197469143963742.post-35259681097963281262014-07-02T14:30:46.474-04:002014-07-02T14:30:46.474-04:00If Rickettsia prowazekii is an obligate, intracell...If Rickettsia prowazekii is an obligate, intracellular pathogen, how are some strains able to persist for several days and even months in dry feces? One would think that the host cells would have dried out and died. It would be interesting to know if processes of genetic exchange such as transformation or conjugation, played a role in giving this special characteristic to these strains.<br /><br />Also, it didn’t seem like this was mentioned but are the mites which are vectors for Scrub typhus, transmitting the pathogen via the injection of enzymes? Or is it the same as the other vectors; the organism is in the feces and are introduced by scratching the feeding site?<br /><br />The transovarial transmission of Orientia tsutsugamushi from mother to eggs is interesting in that the offspring do not have to come in contact with an infected host; they are all born with the ability to infect. If this were a different microorganism, for example, the R.prowazekii, this mode of transmission from mother to offspring could have severe consequences in disease outbreak.<br /><br />--Sofia OluwoleAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-3492197469143963742.post-31101130091342998532013-07-16T12:45:43.691-04:002013-07-16T12:45:43.691-04:00It's amazing how 3 diseases that fall under th...It's amazing how 3 diseases that fall under the same category of Typhus can have such different infection ecologies, reservoirs, and epidemiology. How were these diseases classified together? CBethanyhttps://www.blogger.com/profile/12037293870094382538noreply@blogger.comtag:blogger.com,1999:blog-3492197469143963742.post-72085125175072941572013-07-05T15:01:03.338-04:002013-07-05T15:01:03.338-04:00Tamara brings up interesting points again. I'm...Tamara brings up interesting points again. I'm not sure there are foolproof methods for warding off typhus. CDC recommends insect repellents, self-examination for vectors after visits to endemic areas, and protective clothing. <br />Wars in places like Vietnam, Korean, the South Pacific, and Europe in the 20th century brought people into close proximity with typhus-carriers in their natural habitats. These wars also thrust many people into overcrowded, unsanitary living conditions. Typhus outbreaks in concentration camps is just one example of how the ravages of war often occur at the microscopic level. Anonymoushttps://www.blogger.com/profile/15607806465284324873noreply@blogger.comtag:blogger.com,1999:blog-3492197469143963742.post-19846011067163234892013-07-03T16:43:54.504-04:002013-07-03T16:43:54.504-04:00The high estimated prevalence (up to 50%) of the s...The high estimated prevalence (up to 50%) of the scrub typhus/tsutsugamuchi during WWII was mentioned above. I think it is important to note that along with poverty, similar conditions may arise during wartime and in prison populations. Indeed, the first time I heard of typhus was with respect to the Holocaust, where there were often outbreaks of typhus among the prisoners of concentration camps. The methods to prevent outbreaks among captive populations, such as shaving heads and removing clothes upon entry, double as methods of humiliation and psychological suppression.<br /><br />In a free population, what is the best way to halt a typhus outbreak? If opening a laundromat is not feasible.Tamara Nowakowskihttps://www.blogger.com/profile/00270909140675173957noreply@blogger.comtag:blogger.com,1999:blog-3492197469143963742.post-56410956214957213632013-03-28T11:27:46.218-04:002013-03-28T11:27:46.218-04:00The three forms of typhus are cause by different s...The three forms of typhus are cause by different species of bacteria, not viruses. While it is possible to be infected by all three simultaneously, the epidemiology and ecology of each is quite different so it would be very rare for someone to experience an infection with all three organisms. Michael Walshhttps://www.blogger.com/profile/05038031388622939797noreply@blogger.comtag:blogger.com,1999:blog-3492197469143963742.post-85201089426122997672013-03-27T16:49:58.138-04:002013-03-27T16:49:58.138-04:00is it possible to be infected with all three versi...is it possible to be infected with all three versions of the virus?<br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3492197469143963742.post-15225650949718306222012-07-20T16:29:42.015-04:002012-07-20T16:29:42.015-04:00I did some research to answer your question, and i...I did some research to answer your question, and it seems like washing clothes in cold water would not be effective in killing the pathogen. Water that is at least 140 Fahrenheit is required to kill the lice. Cold can also be used, but killing the lice requires freezing for 24 hours. In a setting of limited resources, it seems like boiling water would be more realistic than access to a freezer.Diana Juliehttps://www.blogger.com/profile/05608586033578150296noreply@blogger.comtag:blogger.com,1999:blog-3492197469143963742.post-41011724314506170522012-07-18T16:18:57.084-04:002012-07-18T16:18:57.084-04:00body lice live in clothing rather than the host, i...body lice live in clothing rather than the host, i was wondering that whether or not washing clothes with hot versus cold water can kill the pathogen. Then again water being a rare commodity in some part of the world makes it hard to eradicate body licer guervilnoreply@blogger.comtag:blogger.com,1999:blog-3492197469143963742.post-55680979858242443672011-08-01T15:54:48.446-04:002011-08-01T15:54:48.446-04:00Max-
According to the World Health Organization, ...Max-<br /><br />According to the World Health Organization, there is an estimated 2.16 million cases (prevalence) of typhus in the world and over 215,000 annual deaths. Also, here is a link to an article that looks at the burden of this disease in Asia, which accounts for 90% of the cases. http://www.who.int/bulletin/volumes/86/4/06-039818/en/index.htmlCraig Nessnoreply@blogger.comtag:blogger.com,1999:blog-3492197469143963742.post-60376238121842449192011-07-19T23:39:47.882-04:002011-07-19T23:39:47.882-04:00I'd be curious to know a little bit more of th...I'd be curious to know a little bit more of the global prevalence of typhus (incidence, prevalence, etc.) Also would be curious to hear about the typhus vaccine, if it has been successful and if it is available for all three varieties of the disease. The connection between availability of water and the frequency of washing clothes was an interesting one that I would not have considered before.Max Padgetthttps://www.blogger.com/profile/13723537888752035874noreply@blogger.comtag:blogger.com,1999:blog-3492197469143963742.post-15972317930592303232011-07-13T16:43:07.467-04:002011-07-13T16:43:07.467-04:00I think it is very interesting how a fully develop...I think it is very interesting how a fully developed flea emerges from its puparium only when a host is near. Some factors were mentioned on the signals the fly but how can the flea understand that the body heat or CO2 it senses is specifically from its host.Janenoreply@blogger.comtag:blogger.com,1999:blog-3492197469143963742.post-29286524437229661042011-07-12T12:46:35.038-04:002011-07-12T12:46:35.038-04:00Murine typhus is endemic to the southwestern US, b...Murine typhus is endemic to the southwestern US, but not in the New York City area. Rickettsialpox is endemic in the New York area, however. Domestic mice serve as the reservoir for rickettsialpox, and the bacterium, Rickettsia akari, is vectored by the mouse mite.Michael Walshhttps://www.blogger.com/profile/05038031388622939797noreply@blogger.comtag:blogger.com,1999:blog-3492197469143963742.post-22861829341249991352011-07-06T14:24:22.727-04:002011-07-06T14:24:22.727-04:00Claire, that’s a good point you make but murine ty...Claire, that’s a good point you make but murine typhus does not seem to such a great problem in NYC, although it is of concern in other parts of the United States (Central and Southwest). Incidence is especially high in port cities and during the hot summer months when there is an abundance of fleas. Since typhus occurs through close contact between humans and rodents, is it possible that insecticide use also helps mitigate the problem?Pennie Gnoreply@blogger.comtag:blogger.com,1999:blog-3492197469143963742.post-85272492474502387262011-07-06T14:03:15.831-04:002011-07-06T14:03:15.831-04:00i am not sure about now but i did find an article ...i am not sure about now but i did find an article about wild rats in NYC in the 1930's and the the danger of infection of Murine Typhus. Since we still have so many wild rats in NYC, i guess that would still be relevant today.The transmission from rodent to household pet would probably depend on the contact the pet has with not only rodents but also fleas.<br /><br />Jamal BurkeAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-3492197469143963742.post-74124205730064478822011-07-05T14:54:09.722-04:002011-07-05T14:54:09.722-04:00With rodents being the primary reservoir for R. ty...With rodents being the primary reservoir for R. typhi, how prevalent is Murine typus in a city like NY where rodents outnumber humans 12:1? Also, how likely is transmission of the pathogen from infected rodent to a household pet which could then pass it onto a human host ?Clairenoreply@blogger.com