Travel Medicine: Diseases with Regional Patterns

[Music] travel medicine a closer look at the world map are you looking for information on diseases with regional patterns in this chalk talk episode we’ll provide you with a general overview and brief introduction on diseases to consider this includes distribution patterns modes of transmission and main symptoms so what are we waiting for let’s go explore the map of the world schistosomiasis is a parasitic disease acquired by contact with contaminated freshwater it’s caused by schistosomiasis also known as blood flukes the parasites usually live in freshwater where they mature in the snails the infectious larvae also termed cirque Aria can penetrate the skin when humans come into contact with contaminated water this can cause a periodic maculopapular rash at the point of entry commonly known as swimmers egde the parasites then migrate to the liver apart from a local reaction most infections are asymptomatic however in some individuals the eggs or adult worms are recognized by the immune system resulting in katha yama fever an acute form of schistosomiasis symptoms include fever cough and angioedema depending on the schistosomiasis bladder resulting in two main forms of chronic schistosomiasis these forms occur in response to egg deposition and are the result of chronic inflammation intestinal schistosomiasis presents with abdominal pain and bloody diarrhea whereas clinical findings in urine total schistosomiasis ardha syria and Hema Turia if the eggs enter the bloodstream they’re transported to other organs such as the liver kidney or central nervous system schistosomiasis is the leading cause of portal hypertension worldwide the regional distribution of the different chronic forms depends on the distribution pattern of the parasite intestinal schistosomiasis is prevalent in South America and Asia whereas your genital schistosomiasis is more common in the Middle East and northern Africa both forms are frequently observed in other regions of Africa the only preventive measure against infection is to avoid contact with freshwater in endemic areas schistosomiasis can be effectively treated with the anthelmintic Raisa quintal the most historically feared disease by travelers is malaria it clinically presents with nonspecific findings such as fever nausea and vomiting after an incubation period of 1 to 6 weeks despite its prevalence in Africa South America and Southeast Asia approximately 90% of more than 200 million annual cases of malaria occur in Africa several types of malaria exist which are caused by different Plasmodium species among these Plasmodium falciparum is the most common accounting for approximately three-quarters of cases worldwide the female Anopheles mosquito acts as a vector transferring sporozoites through their bite the sporozoites enter the bloodstream of the human host and migrate to the liver after maturation they re-enter the bloodstream and invade your ether sites which rupture and release Mehra’s OS that induce febrile inflammatory response as a preventative measure travelers are strongly advised to use exposure prophylaxis such as mosquito repellents and mosquito nets in addition chemo prophylaxis can be used the drug of choice depends on the destination and duration of stay and considers the current status of drug resistance however anti malarial drugs don’t prevent infection instead they alleviate clinical manifestations by attacking developmental forms of the parasite due to the strong adverse effects of chemo prophylaxis a detailed look at the local risk of malaria should be made as a general rule of thumb there’s no risk of malaria infections in locations with temperatures below 15 degrees Celsius which are in various high-altitude areas in the tropics another mosquito-borne febrile disease is dengue fever it’s caused by infection with dengue virus and is primarily transmitted by the ATS a chipped eye mosquito therefore the risk areas of dengue infection cover most of the distribution areas of ATS a jib ty dengue is found in tropical and subtropical regions worldwide especially in Southeast Asia but also in Central and South America Africa Oceania and North East Australia although approximately 90% of infected individuals remain asymptomatic a severe course with hemorrhagic fever occurs in one to two percent of cases dengue hemorrhagic fever is characterized by bleeding shock and organ dysfunction and can be fatal progression to severe forms occur especially in patients with either concurrent infection with different serotypes of dengue virus or in patients immune to one or more serotypes as a result of previous infection a live attenuated vaccine is currently available in some endemic countries however it isn’t recommended for travelers dengue prevention is limited to avoiding mosquito exposure in endemic areas eighty’s mosquitoes are also involved in the transmission of another hemorrhagic fever yellow fever this disease is currently more localized than dengue fever and malaria most yellow fever infections occur in sub-saharan Africa between 15 degrees north and 18 degrees south of the equator other regions of risk for travelers are the tropical regions of northern South America this region is also referred to as the yellow fever Belt the disease is caused by yellow fever virus which can result in viral hemorrhagic fever clinical manifestations include liver dysfunction renal failure disseminated intravascular coagulation and shock the most effective preventative measure against yellow fever is vaccination with a single dose vaccine available that provides lifelong protection some countries require travelers coming from yellow fever endemic areas to provide proof of vaccination the protozoan parasite Trypanosoma brucei eye is restricted to sub-saharan Africa giving rise to a disease that is best known as sleeping sickness or African trypanosomiasis the parasites are transmitted by the tsetse fly there are two different forms of the disease that are caused by different pathogens the West African form and the East African form which are designated by their Geographic distributions patients initially present with painful red swelling at the site of the bite this is followed by a Hema lymphatic phase where the patient’s develop intermittent fever lymph node swelling anemia and immune reactions in different organ systems such as the central nervous system and the cardiac system the neurological phase begins a few months two years after infection in the case of West African trypanosomiasis or within a few weeks in the case of East African trypanosomiasis clinical findings include headache daytime somnolence which gives rise to its name sleeping sickness ataxia delayed hyperesthesia cachexia and eventually coma the only preventative measure is to avoid exposure by using insect repellents wearing long sleeve clothing and avoiding areas inhabited by the tsetse fly as the protozoan parasite Trypanosoma is not limited to Africa it should come as no surprise that an American form of trypanosomiasis exists the disease is widely known as Chagas disease Shaka’s disease is endemic in Central and South America and is transmitted by the tria to mean bug also known as the kissing bug infections reported in North America and Europe are either imported or infrequently acquired through blood transfusion organ transplantation or vertical transmission from mother to fetus shortly after infection patients develop a characteristic local skin lesion at the site of the bite which is also known as asha Goma the acute phase of infection manifests with nonspecific symptoms such as fever malaise and generalized lymphadenopathy the asymptomatic intermittent phase is followed by a chronic phase with a development of cardiomyopathy characterized by arrhythmias mega esophagus and megacolon in contrast to sleeping sickness the central nervous system is rarely affected in Shaka’s disease prophylactic measures for travelers are preventing exposure to the vector by using insect repellents and bed nets treated with insecticides a disease that poses a risk for individuals traveling to the northern hemisphere is Lyme disease also termed borreliosis Lyme disease is caused by bacteria of the Borrelia type which are transmitted by ticks the vector is most prevalent in areas endemic for Lyme disease infected ticks can be found in the northeastern and upper Midwestern US and Europe as well as in Russia if left untreated Lyme disease can proceed in three stages beginning with an early localized rash eventually causing a systemic infection involving joints skin and the central nervous system as there is no vaccine available against Lyme disease preventative measures comprised of preventing exposure to ticks as well as the immediate removal of the tick after biting removal lowers the risk of infection as transmission usually occurs after an attachment time between 12 and 24 hours in addition close observation of the bite side is advised because the presence of a classical erythema migrans may indicate infection however not all cases of Lyme disease are accompanied by erythema lyme disease can be treated with antibiotics with early treatment resulting in the highest success rates therefore any sign of infection should signal the start of further Diagnostics and if indicated treatment other viral infectious disease to be on the lookout for in the northern hemisphere is tick-borne encephalitis which is caused by tick-borne encephalitis virus in short TB evey apart from its regional distribution transmission is more frequent during summer with infection rates highest during this period approximately 90% of infections remain asymptomatic however the remaining 10% initially show flu-like symptoms and fever after a fever free interval the central nervous system is affected typically manifesting as meningoencephalitis treatment of meningoencephalitis is supportive and based on the severity of symptoms but usually leads to full recovery as a preventative measure vaccines against TB evie are available however they are only recommended to individuals traveling to endemic regions where they are more likely to be exposed to ticks preventative measures to avoid tick bites are generally advised immediate removal of the tick after biting doesn’t further reduce the risk of infection with TB evey as the virus is transferred directly after biting one well-known disease that occurs on a global scale is rabies the disease is often fatal and is caused by lyssavirus which include the rabies virus in encephalitic rabies initial symptoms include agitation confusion and hypersalivation followed by coma and death rabies is usually transmitted through the bite of an infected animal most likely a dog or bat the region’s high at risk for rabies infection are Africa and Southeast Asia however transmission through wild animals can occur in almost all geographic locations including Central and South America and Europe as there is no drug available against rabies virus infection prophylaxis is highly recommended pre-exposure rabies vaccination is ideal however treatment consisting of post-exposure vaccinations and rabies immunoglobulin after suspected exposure is particularly effective so let’s summarize what we’ve just covered individuals preparing to travel should be informed about potential risks in the countries that they’re traveling to this includes determining whether the regions are at risk for diseases that can be prevented by administering a vaccine prior to departure also it’s usually quite helpful to be cautious about drinking water sources and food especially if it’s not well cooked for any outdoor activities it’s advisable to minimize exposure to insects which are often vectors of pathogens we do admit that it’s difficult to remember all of this information but don’t worry it’s all available in our library so let’s see how much you know about these travel relevant diseases in our quiz 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