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MBIO 4300 Midterm Exam Study Guide: Infectious Diseases in Latin America, Exams of Biology

Oxford House CollegeBiology

This comprehensive study guide covers key concepts and information related to infectious diseases prevalent in latin america, focusing on topics like dengue, zika, yellow fever, chikungunya, and hiv. It provides detailed explanations of disease characteristics, transmission mechanisms, symptoms, treatment options, and prevention strategies. The guide also includes questions and answers to help students prepare for their mbio 4300 midterm exam.

Typology: Exams

2024/2025

Available from 04/16/2025

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MBIO 4300 Midterm.
Latest Updated Exam Study Guide
2025/2026.
Physical factors the affect infectious diseases - ans- Access to affordable food
- Access to proper housing
Societal factors the affect infectious diseases - ans- Clean water
- Contact with vectors (animals)
- Access to health care
- Urbanization (increase in population density)
Cultural and religious factors the affect infectious diseases - ans- Traditional medicine
- Food prep methods
- Cultural practices that promote poor practice
Political factors the affect infectious diseases - ans- Healthcare funding and access for
citizens
- Failure to acknowledge issues with diseases
- Conflict
Why is healthcare overlooked by some governments - ans- Developing nations often
prioritize military development rather than healthcare
How does population size effect disease spread - ans- Small isolated communities are hit
hardest due to lack of immunity
- Density increase leads to easier spread
How are zoonotic infections contracted - ans- Human engagement with animals
How does climate change affect disease spread - ans- Increasing temp allows vectors of
infection to thrive
How does deforestation affect disease spread - ans- Increased opportunity for larvae
- Increase number of vectors
How did air travel contribute to spread of diseases - ans- People of have contracted the
pathogen could be asymptomatic and board planes to places that are not infected
How does poverty affect contraction of diseases - ans- Vaccines are not always affordable
- Clean water is not available
- Poor sanitation/living conditions
How can education help prevent spread - ans- Understanding how a diseases spreads can lead
to precautionary measures
How does a tropical environment affect spread - ans- Allows for survival of vectors
- High amount of precipitation also aids
Why is health care provider retention a problem in Latin America - ans-More and more
professionals leaving which results in lack of trust
How does socioeconomic discrimination affect - ans- Stigma can lead to less testing resulting
in undertesting
- Also results in lack of proper healthcare
Why are some diseases labeled as forgotten diseases - ans- Lack of prioritization of illnesses
that effect the poor
What is Dengue virus - ans- DENV
- +ssRNA arbovirus
- Immunity of one does not carryover to others
How is Dengue spread in Latin America - ans- Aedes spp. mosquitos
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Download MBIO 4300 Midterm Exam Study Guide: Infectious Diseases in Latin America and more Exams Biology in PDF only on Docsity!

Latest Updated Exam Study Guide

Physical factors the affect infectious diseases - ans- Access to affordable food

  • Access to proper housing Societal factors the affect infectious diseases - ans- Clean water
  • Contact with vectors (animals)
  • Access to health care
  • Urbanization (increase in population density) Cultural and religious factors the affect infectious diseases - ans- Traditional medicine
  • Food prep methods
  • Cultural practices that promote poor practice Political factors the affect infectious diseases - ans- Healthcare funding and access for citizens
  • Failure to acknowledge issues with diseases
  • Conflict Why is healthcare overlooked by some governments - ans- Developing nations often prioritize military development rather than healthcare How does population size effect disease spread - ans- Small isolated communities are hit hardest due to lack of immunity
  • Density increase leads to easier spread How are zoonotic infections contracted - ans- Human engagement with animals How does climate change affect disease spread - ans- Increasing temp allows vectors of infection to thrive How does deforestation affect disease spread - ans- Increased opportunity for larvae
  • Increase number of vectors How did air travel contribute to spread of diseases - ans- People of have contracted the pathogen could be asymptomatic and board planes to places that are not infected How does poverty affect contraction of diseases - ans- Vaccines are not always affordable
  • Clean water is not available
  • Poor sanitation/living conditions How can education help prevent spread - ans- Understanding how a diseases spreads can lead to precautionary measures How does a tropical environment affect spread - ans- Allows for survival of vectors
  • High amount of precipitation also aids Why is health care provider retention a problem in Latin America - ans-More and more professionals leaving which results in lack of trust How does socioeconomic discrimination affect - ans- Stigma can lead to less testing resulting in undertesting
  • Also results in lack of proper healthcare Why are some diseases labeled as forgotten diseases - ans- Lack of prioritization of illnesses that effect the poor What is Dengue virus - ans- DENV
  • +ssRNA arbovirus
  • Immunity of one does not carryover to others How is Dengue spread in Latin America - ans- Aedes spp. mosquitos

Latest Updated Exam Study Guide

  • Prevalent in tropical areas What is the best way to prevent Dengue spread in Latin America - ans- Vector control
  • Chemical treated mosquito nets How do mosquitos inoculate humans with Dengue in Latin America - ans- Immune cells are recruited and macrophages become infected
  • Tissue damage when immune system activates
  • Migration of infected cells in lymphatic fluid leads to viremia
  • Mosquitos take blood from infected allowing them to infect other humans What are some of the symptoms of Dengue in Latin America - ans- Flu-like
  • High fever (40), headache, myalgia, bone and joint pain, swollen glands
  • Some develop rash What are some of the more rare symptoms of Dengue in Latin America - ans- Break bone infection
  • Saddleback fever can occur, high temp to low temp back to high What are the clinical representation of Dengue in Latin America - ans- Neutropenia (neutrophils)
  • Lymphocytosis (lower than normal lymphatic cells)
  • Thrombocytopenia (thrombocytes decrease) What symptoms are common in untreated dengue - ans- Hemorrhagic fever due to low immunity
  • Organ failure due to drop in blood pressure What is dengue vaccine and how is it administered - ans- Tetra valent live attenuated (dengvaxia)
  • 3 doses 6 months apart
  • Given to 9 - 45 yr old's Can the dengvaxia be given to anyone in age range - ans- Only given to people that already have been infected
  • Antibody dependent enrichment What is antibody dependent enrichment (ADE) and why is it a concern for people who have not been infected - ans- Antibodies produced do not neutralize virus but facilitate infection How did humanized mice help with understanding diseases - ans- Able to emulate human immune system to a degree
  • Allowed us to measure cytokine levels
  • Indicated that mosquito saliva alone can induce immune responses as long as 7 dats after bite Characteristics of zika virus in Latin America - ans- Enveloped, +ssRNA
  • Transmitted by mosquitos (aedes spp.)
  • Transmission from sex and blood also possible
  • Shown to prefer replication in prostate over epithelial cells How does an enveloped virus differ in terms of infectivity compared to a naked virus - ans- Enveloped: lose infectivity faster due to degradation of envelope
  • Does not happen with naked viruses

Latest Updated Exam Study Guide

  • Urban: from people who return to urban settings after being in jungle (human to human) When and how long are humans infectious for with yellow fever - ans- Shortly prior to fever onset and lasts for 5 days
  • Needle-stick and transfusion is possible What does 3 phases of yellow fever infection in Latin America - ans1. Infection
  1. Remission
  2. Intoxication What is the infection step like in yellow fever - ans- Fever, headache, jaundice, nausea, fatigue and myalgia
  • Jaundice What is the Remission step like in yellow fever - ans- Most patients resolve the infection entirely during this period
  • Small proportion of patients this only lasts 2-24 hours What is the intoxication step like in yellow fever - ans- Severe hemorrhagic diseases
  • Impacts liver (hepatitis) and kidneys fail
  • 50% mortality rate within one week of onset with severe disease Why is early diagnosis of yellow fever difficul - ans- Closely resemble other infections in area
  • Use PCR on blood on urine samples
  • ELISA can detect antibodies but flavy increases false positives Are there any vaccines for yellow fever - ans- Live attenuated vaccine 80% effective
  • Given 10 days ahead of travel
  • 99% within 30 days
  • Provides lifelong immunity How are yellow fever vaccines made - ans- Made by serial passage What causes Chikungunya Virus in Latin America - ans- +ssRNa
  • Arbovirus
  • Togaviridae family
  • Alphavirus Old world VS new world Chikungunya virus - ans- Old: Severe polyarthralgia
  • New: encephalitis How is Chikungunya transmitted in Latin America - ans- Mosquito Aedes genus
  • Infectious after a few hours for the rest of its life What are some symptoms of Chikungunya - ans- Fever and extreme arthralgia
  • Myalgia, joint swelling, fatigue, rash
  • Sometimes neurological symptoms, eye issues How do you treat Chikungunya virus - ans- No virus specific treatment exists
  • NSAIDS How to diagnosis Chikungunya virus - ans- ELISA
  • PCR How to prevent Chikungunya virus - ans- Vector control What does U=U mean - ansUndetectable = Untransmittable What causes HIV in LAC - ans- Enveloped ssRNA

Latest Updated Exam Study Guide

  • Retroviridae
  • Lentivirus genus How is HIV transmitted - ans- Blood
  • Sexual activates
  • Mother to child across placenta How to treat HIV - ans- Antivirals reduce viral load
  • Which results into U=U What is the acute phase of HIV - ans- Develops few days after infection
  • Asymptomatic What is stage 1 HIV - ans- CD4 cell count at least 500 cells of blood account at least 29% of lymphocytes What is stage 2 HIV - ans- CD4 cell count is between 200 and 499 cells of blood account at least 14-28% of lymphocytes What is stage 3 HIV - ans- AIDS
  • CD4 cell count drops and less 14% of lymphocytes Which groups are at risk of HIV - ans- MSM
  • Sex workers
  • Transgender woman
  • IV drug user
  • Migrants
  • Incarcerated What is Dolutegravir and is it administered - ans- Integrase inhibitor
  • Used for all groups including pregnant women
  • Taken once daily with decreased side effects What PrEP and is it administered - ans- Pre-exposure prophylaxis
  • Truvada pill (nucleoside inhibitors of reverse transcriptase)
  • Taken by individuals who are high risk Downsides of taking PrEP - ans- Requires regular testing and only by HIV negative patients
  • If not taken properly increases chances
  • Kidney and liver as well as decreased bone density What PEP - ans- Post-exposure prohylaxis
  • 3 HIV medications taken within 72 hours of exposure for 28 days
  • Tenofovir, emtricitabine and raltegravir or dolutegravir What is the 90/90/90 goal? - ansTo get "90 % of people living with HIV to know they have the virus, 90 % of those who know they are infected to be receiving sustainable antiretroviral treatment, and 90 % of those people on treatment to have sustainable suppression of their virus — 90 - 90 - 90 — by 2020" What causes Chagas Disease in LAC - ans- American Trypanosomiasis
  • Parasitic by Trypanosoma cruzi How is Chagas Disease spread - ans- Insect vector, triatomine bugs which bite at night
  • Prevalent in poor areas
  • Spread in fecal matter
  • Cross placenta and blood transfusion

Latest Updated Exam Study Guide

  • Guyana
  • Dominican Republic
  • Brazil How is lymphatic filariasis transmitted? - ans- Nematodes of Filariodidea family
  • Microfiliareae can be picked up by mosquitos of the Culex, Aedes and Anopheles geneus How does Lymphatic Filariasis effect the body from a clinical stand point - ans- Adult filariodidea nest in lymphatic vessels causing dysregulation of immune system
  • Blocks flow due to tangled structure causing lump
  • Live for 10 yrs Symptoms of acute infection of Lymphatic Filariasis - ans- Episodes with localized inflammation
  • Occur due to immune response to parasite or 2 degree infection due to dysregulated immune function
  • Symptoms of chronic infection of Lymphatic Filariasis - ans- Lymphedema (swelling due to accumulation of lymphatic fluid)
  • Elephantiasis (thickening of skin and soft tissues) in breasts and genital tissues
  • Hydrocele: fluid filled pocket in testicle Treatment for Lymphatic Filariasis - ans- Ivermectin
  • Albendazole
  • Diethylcarbamazine
  • Kills larva but not adult How is treatment for Lymphatic Filariasis administered - ans- MDA (mass drug administration)
  • 2 pill regime with albendazole and diethylcarbamazine
  • Given to adults once a year and children twice a year What are alternative treatments for Lymphatic Filariasis - ans- Elevation of affected limbs
  • Exercise to circulate fluid
  • Surgery for hydrocoele How to diagnose Lymphatic Filariasis - ansMicroscopic examination of blood samples What causes Leishmaniasis and how is it transmitted? - ans- 20 spp. of Leishmania parasite
  • Spread by bite from phlebotomine sand flies (active in evening and night) What are the types of Leishmaniasis and where are they found - ans- Cutaneous: Brazil and Columbia
  • Visceral (organs): Brazil
  • Mucosal: Brazil, Bolivia and Peru
  • Post-kala-azer dermal How does Leishmaniasis infect the body - ans- Infects macrophages (aids tissues with immunity)
  • Macrophage lysis releasing amastigotes that infect naïve macrophages
  • Sand flies pick up amastigotes that proliferate forming infectious promastigotes Symptoms of cutaneous Leishmaniasis - ans- Skin sores after months
  • Macular (red), papular (puss) or ulcerated (red, puss and ooze)
  • Dermal macrophages

Latest Updated Exam Study Guide

  • Slow healing
  • Severe scars Symptoms of visceral Leishmaniasis - ans- Can occur years after
  • Fever
  • Weight loss
  • Decreased blood cell counts
  • Swelling of liver and spleen
  • Damaging to immune system high risk of secondary infection Symptoms of mucosal Leishmaniasis - ans- Infects mouth/nose
  • Can occur years later How can we diagnose Leishmaniasis - ans- ELISA
  • PCR to detect parasite DNA
  • Microscopic analysis of samples from ulcers or bone marrow How is Leishmaniasis treated - ans- Pentavalent antimonials
  • Amphotericin B or liposomal amphotericin B How is treatment of Leishmaniasis administered - ans- Amphotericin B or liposomal amphotericin B
  • Need to be given daily via parenteral route for min of 3 weeks Side effects of Leishmaniasis treatment - ans- Terrible toxicity associated with poor compliance
  • Nausea, vomiting, diarrhea, myalgia, rash, liver toxicity and sometimes cardiac toxicity What causes Schistosomiasis and where is it found - ans- Schistosoma mansoni
  • Brazil, Venezuela and Caribbean How is schistosomiasis transmitted? - ans- Blood flukes released into water by fresh water snails
  • Humans contact infected water How does Schistosomiasis occur in the body - ans- Schistosomes penetrate skin and develop into adults
  • Live in blood vessels
  • Females release eggs that can be excreted through urine and feces into water supply
  • Some embed in tissues - > immune response - > tissue damage What is intestinal Schistosomiasis and symptoms - ans- Caused by bodies reaction to parasitic eggs
  • Diarrhea, abdominal pain, peritoneal (belly) edema, abdominal hypertension, blood in stool How is schistosomiasis diagnosed? - ans- Detection of parasitic eggs in stool or urine using microscopy Treatment for Schistosomiasis - ans- Preventative praziquantel chemotherapy
  • Anthelmintic causes muscle spasms and paralysis of worm - > released from endothelium What causes Trachoma and symptom - ans- Chlamydia trachomatis
  • Blindness How is Trachoma transmitted - ans- Close contact
  • Insects when in contact with discharge from infected tissues Where is Trachoma found - ans- Brazil

Latest Updated Exam Study Guide

How is Malaria diagnosed - ans- Microscopy with giemsa stain Treatment for Malaria - ans- Artemisinin-based combination therapy (ACTs)

  • Damages plasmodium proteins killing cells
  • Resistance builds Preventative treatment for Malaria - ans- Prophylactics
  • Chloroquine, doxycycline, primaquine, mefloquine What causes Tuberculosis - ans- Mycobacterium Tuberculosis
  • Mycobacterium africanum How is tuberculosis transmitted? - ans- Small infectious droplets
  • Only few bacterial cells are most effective How does Tuberculosis effect the body - ans- When bacterium reach alveoli it is phagocytosed by macrophages
  • If macrophages does not destroy bacterium it will multiply eventually moving to other tissues via lymphatic system or blood
  • Immune cells are used at site of infection forming a granuloma
  • Granuloma is where MTB replication occurs while other MTB cells are dormant What is latent TB - ans- Cells are actively replicating are destroyed by the immune response
  • Infected macrophages can undergo apoptosis leading to engulfment by another macrophage
  • It can also become necrotic
  • Non-communicable
  • Asymptomatic and unable to spread bacterium
  • Controlled by IMS What is symptoms active Tuberculosis - ans- Pulmonary TB - > communicable
  • Productive cough lasts for 2 weeks
  • Thick, cloudy mucus
  • Sputum may contain blood How is TB diagnosed? - ans- Mantoux test: injection of tuberculin under skin in forearm, read 48 - 72 hrs later, size of welt develops indicates likelihood of TB, induration must be measured
  • If active acid fast stain on sputum smear and left to grow for 24 hrs
  • Chest X-ray and CT scan to look for calcified lesions form past infections What is extra pulmonary TB? - ans- Involves organ systems outside of the respiratory tract
  • Can occur with pulmonary TB

Treatment for latent Tuberculosis - ans- 1 medication, isoniazid taken for 9 months

  • 2 medications, rifampin and isoniazid for 3 months Treatment for active Tuberculosis - ans- 4 medications taken for 2 months (rifampin, isoniazid, ethambutol and pyrazinamide
  • 2 medications for another 4 months (isoniazid and rifampin) What is multi-drug resistant TB resistant to (MDR-TB) - ans- Resistant to rifampicin and isoniazid
  • Treated with second line drugs

Latest Updated Exam Study Guide

What is extensively-drug resistant TB resistant to (XDR-TB) - ans- Resistant to rifampicin, isoniazid and second line drugs

  • Needs much longer therapy What is the BCG vaccine - ans- Bacille Calmette-Guerin vaccine for TB using live attenuated strain of M. bovis
  • Given in single dose
  • Limited effectiveness
  • Given to high risk groups with intent to not prevent infection but prevent severe TB Is there a vaccine for pneumonia - ans- Yes but they are vaccines for other conditions that worl
  • H. influenza
  • Steptococcus - pneumoniae
  • Measles What are the 4 ways pneumonia can occur - ans- Bacteria
  • Virus
  • Fungal (hospital acquired)
  • Parasite (HIV) What is the most common cause of pneumonia and why is this interesting - ans- Streptococcus pneumoniae
  • Normal member of respiratory tract
  • Causes disease when it enters the lower respiratory tract What is the main difference between hospital acquired pneumonia vs community acquired - ans- Hospital acquired often has high antibiotic resistance Pneumonia symptoms - ans- Cough
  • Difficulty breathing
  • Chest recoils during inhalation and rapid breathing
  • Fever maybe How is pneumonia treated - ans- Amoxicillin antibiotic What causes Onchocerciasis? - ans- Onchocerca volvulus
  • Parasitic filarial worm How is onchocerciasis transmitted? - ans- Black flies
  • Genus Simulium
  • Breed in reivers and streams with fast moving water How can we diagnose Onchocerciasis - ans- Testing of urine, blood and sputum can sometime show microfilariae Symptoms of Onchocerciasis - ans- Eosinophil activation
  • Inflammation causing pruritis (itch)
  • Disfiguring changes to skin (loss of elasticity, leopard skin)
  • Nodules are many but not painful How does Onchocerciasis cause blindness - ans- Immune response to parasite
  • Damage to circulation in eye (glaucoma)
  • Damage to retina (blindness) How is Onchocerciasis diagnosed - ans- Microscopic detection of microfilariae in skin biopsy

Latest Updated Exam Study Guide

  • Inability to sleep at night How is African sleeping Sickness diagnosed - ans- Lymph node samples
  • Lumbar puncture to evaluate cerebrospinal fluid How does the parasite in African sleeping Sickness avoid immune detection - ans- Typanosomes vary glycoprotein expressed on surface
  • Only 1 active at a time
  • Able to quickly remove and insert another protein variant
  • Avoids antibody detection What is the treatment for first stage of African sleeping Sickness - ans- Pentamidine for gambiense subspecies
  • Suramin used to treat rhodesciencse What is the treatment for stage 2 African sleeping Sickness - ans- Melarsoprol
  • Eflornithine
  • Nifurtimox
  • Much more harder to treat when CNS What is severe diarrheal disease defined as - ans- More than 10 watery stools per day What is moderate diarrheal disease defined as - ans- More than a few less than 10 watery stool a day What is mild diarrheal disease defined as - ans- Few watery stools a day How long does acute watery diarrhea last - ans- Hours to days What is dysentery diarrhea - ans- Bloody diarrhea How long does persistent diarrhea last - ans>14 days What are common bacterial causes of diarrhea - ans- Vibrio cholerae
  • E.coli What is a common viral cause of diarrhea - ans- Rotavirus What are common parasitic causes of diarrhea - ans- Cryptosporidium parvum and Hominis
  • Giardia lamblia and intestinalis What are different ways diarrheal diseases are spread - ans- Person to person
  • Zoonotic to person
  • Contaminated water How does an undernourished body relate to severe diarrheal diseases - ans- Poorly maintained immune system
  • Further undernourishment
  • Results in stunting What is ORS treatment for diarrheal diseases - ans- Oral rehydration salts
  • 90% effective in reducing mortality How does iCCM help with diarrheal diseases - ans- Integrated community case management
  • Trains healthcare providers on treating with ORS and zinc What is fluid curtailment and how does it affect diarrheal diseases - ans- Less fluid given to children with diarrhea
  • Occurs due to misinformation and beliefs
  • Leads to further dehydration

Latest Updated Exam Study Guide

What are the 3 local beliefs of diarrhea in South Africa - ans- Occurrence due to natural causes

  • Occurrence due to supernatural causes
  • Occurrence due to infectious agent (best for proper treatment) How to treat diarrheal diseases caused by Vibrio cholerae - ans- ORS mixed with 1L of clean water
  • Very severe infection needs IV
  • Antibiotics can be given to decrease duration of diarrhea How can V. cholerae be diagnosed - ans- PCR with culture of stool sample Are there any vaccines for V. cholerae caused diarrheal diseases - ans- Yes
  • Dukoral
  • Sanchol
  • Euvichol How are Cryptosporidium and Giardia contracted - ans- Swimming, bathing and consuming contaminated water
  • From fruits, vegetables and seafood How does being immunocompromised effect infection by Cryptosporidium and Giardia - ans- Self-limiting unless immunocompromised
  • Severe disease in immunocompromised hosts How is Cryptosporidium and Giardia diagnosed - ans- Microscopic examination of fecal samples
  • ELISA and detection kits are available How is cryptosporidium treated - ans- Nitazoxanide
  • Not very effective
  • Children less than 1 cannot take How is Giardia treated - ans- Metronidazole
  • 80% effective but resistance is prevalent Why can it be difficult to seek healthcare for males with HIV in Africa - ans- Stigma of infection What is a common coinfection with HIV in Africa - ans- TB How does HIV relate to economic progress - ans- Expensive to treat
  • Common Why does Africa have the highest amount of HIV + children - ans- Mother to child transmission
  • Through milk or placenta What is the main reason people in Africa do not seek medical attention for HIV - ans- Stigma involved
  • Discrimination from Dr
  • Sex workers as high risk of HIV Difference between HIV-1 and HIV- 2 - ans- 1: Is HIV that is worldwide
  • 2: In west-Africa, slow progressing Similarities between HIV-1 and HIV- 2 - ans- Similar genomic arrangement
  • Both infect CD4 T helper cells

Latest Updated Exam Study Guide

  • Sudden onset is different, Parkinson's takes time What happens when motor neurons are damaged during Japanese encephalitis infection - ans- Flaccid paralysis
  • Life long neurological effects What can we use to test for Japanese encephalitis - ans- Antibody testing
  • MRI for neurological changes
  • Evaluate chemistry of CSF What is the issue with antibody testing of Japanese encephalitis - ans- Cross reactivity with other flavivirus
  • False + Why is timing of Ab testing important with Japanese encephalitis - ans- Too early, Ab not present
  • Too late and class switching occurs What is evaluated in MRI for Japanese encephalitis - ans- No radiation
  • Presence of thalamic lesions What is evaluated in CSF for Japanese encephalitis - ans- Glucose normal
  • Elevated proteins due to Ab
  • Elevated leukocytes (indication of infection) What are the 2 types of vaccines for Japanese encephalitis and which is best - ans- Live attenuated (best)
  • Inactivated How is inactivated vaccine for Japanese encephalitis administered - ans- 2 doses given 1 month apart
  • Recommended booster within a year or 2 of receiving vaccine
  • Used in Na, AUS and Eu Where is the live attenuated vaccine for Japanese encephalitis used - ans- China
  • India
  • Sri Lanka
  • Thailand What causes leprosy in Asia - ans- Mycobacterium leprae What is the issue with culturing leprosy in Asia - ans- Long generation times of 13 days
  • 5 year incubation period Why is it hard to diagnose leprosy in Asia - ans- Symptoms can develop anywhere from 6 months to 20 years after infection What temperature does leprosy in Asia like - ans- Colder temps
  • Similar to that on nose and fingers Where does leprosy in Asia infect - ans- Mucosal sites and skin
  • Can involve eyes, testes, bone and muscle How is bacterium shed from respiratory mucosa if infection in skin for leprosy in Asia - ans- Attaches to respiratory tissue using adhesins via H-bonds What happens when leprosy in Asia spreads to peripheral nerves - ans- Kills neurons due to infected neurons presenting MHC 1 causing cytotoxic T cell response
  • Neurons do not regenerate thus loss of sensation

Latest Updated Exam Study Guide

Where is leprosy most common in Asia - ans- India and Indonesia How does leprosy in Asia cause stigma - ans- Disfigurement

  • Deformation
  • Blindness What is the key determinant of the severity of leprosy in Asia - ans- Immune response Symptoms of Tuberculoid leprosy (paucibacillary leprosy) - ans- Large macular, red , raised borders lesions
  • Hypo or hyperpigmented
  • Loss of sensation
  • Thickened nerves from swelling due to damage
  • Good cell mediated immune response Symptoms of Lepramatous leprosy (multibacillary leprosy) - ans- Multiple, deep, large lesions
  • Can infect hair follicles
  • Ulcerated nodules (foam cells)
  • Saddleback nose when cartilage destroyed Why does resorption of digits occur in Lepramatous leprosy - ans- Recycles in organic material to help fend off infection Main differences between tuberculoid and lepramatous leprosy - ans- Loss of sensation may not occur in lepramatous
  • Nerve thickness not seen in lepramatous How does leprosy spread - ans- Droplet transmission
  • Crowded living conditions increase risk How is leprosy diagnosed - ans- Clinical representation
  • Skin smear stained using af stain
  • Biopsy of nerves/skin allow detection of histological changes associated with infection What is the treatment for paucibacillary leprosy - ans- Rifampicin and dapsone for 6 months
  • Rifampicin taken once per month
  • Dapsone taken daily How to treat multibacillary leprosy - ans- Rifampicin, dapsone and clofazimine for 12 months
  • rifampicin taken once a month
  • Dapsone and clofazimine taken daily What causes typhoid - ans- Salmonella typhi
  • Gram negative Why is salmonella enterica Typhi an issue when systemic - ans- Gram - lipopolysaccharide is potent immune activator
  • Increases vasodilation
  • Decreased blood pressure
  • Results in septic shock What causes paratyphoid - ans- Salmonella enterica paratyphi A How is typhoid spread - ans- Fecal/oral route
  • Indirect person to person
  • Can be shed asymptomatically

Latest Updated Exam Study Guide

  • Obligate intracellular organism
  • Infects endothelial cells lining blood vessels How is typhus spread - ans- Pediculus humanis (lice)
  • Louse collects rickettsia when taking a blood meal
  • Feces or crushed louse can be rubbed into bite wounds Where do typhus vectors like lice prefer to be - ans- Cooler temps in mountainous regions Where does rickettsia multiply - ans- In gut of louse, lysing vector
  • Viable in dead louse for prolonged periods Where does rickettsia replicate in human - ans- Cytoplasm of endothelial cells
  • Prevents phagosome and lysozyme
  • Endothelial cell ruptures releasing rickettisal cells to plasma What happens when lysis of endothelial cells occurs - ans- Damage to vasculature
  • Blood loss
  • Protein loss
  • Shock and multiple organ failure Symptoms during early typhus infection - ans- Sudden high fever for 2 weeks
  • Chills
  • Severe headaches
  • Weakness
  • Exhaustion How do symptoms of typhus change after 1 week - ans- Dark colored macular rash develops on upper trunk, spreads throughout body What makes diagnosis of typhus difficult - ans- Misinterpreted as leptospirosis, typhoid fever, rickettsia, dengue and many others What is Brill-Zinsser disease - ans- Occurs in typhus patients yrs after infection
  • Never cleared initial infection becomes latent
  • Presents as a less severe form of typhus Can Brill-Zinsser disease spread typhus - ans- Yes
  • Bacteremia occurs
  • Rickettsia can be picked up by louse How to diagnose typhus - ans- Immunoglobulin assays (serology)
  • 4 fold increase in antibody titer between acute and convalescent phase
  • PCR possible using blood sample prior to Ab detection What was used in antibody agglutination tests - ans- Proteus vulgaris called Weil-Felix test
  • Antigen from rickettsia used today What is the treatment for typhus - ans- Doxycycline given orally for 7-10 days (twice a day until fever is gone)
  • Single dose therapy also effective How can typhus be prevented - ans- Regular changing of clothes and bedding
  • Permethrin insecticide to dust clothing and bedding What causes nipah virus - ans- Henipavirus What type of virus is nipah virus - ans- Zoonotic What is the natural host of nipah virus - ans- Fruit bat (pteropus)

Latest Updated Exam Study Guide

  • Does not cause disease in bats How was pig to human transmission considered not to be as big a factor for nipah virus - ans- Outbreak in Bangladesh where pig farms are uncommon How is Nipah virus spread? - ans- bats (feces, urine, saliva) contaminated fruit juice
  • Close contact with animals or infected bodily fluid from animals How can nipah virus cause encephalitis - ans- Enter into major organ systems and replicate inside endothelial cells
  • Lungs, kidney, CNS, spleen and lymph nodes Why is nipah virus considered a level 4 pathogen - ans- High mortality rate within 2 weeks of symptoms
  • No effective treatment or vaccine Symptoms of early nipah virus - ans- Headache
  • Sore throat
  • Vomiting
  • Myalgia
  • Fever Symptoms of severe nipah virus - ans- Pneumonia
  • Difficulty breathing
  • Encephalitis How does severe encephalitis present when caused by nipah virus - ans- Swelling of brain, seizures
  • Rapid entry into coma is common after onset of neurological symptoms (can present within 48 hours) What happens to those who can recover from nipah virus induced encephalitis - ans- Recover completely
  • Suffer long term neurological symptoms (seizure disorders)
  • Have recurrent infection and encephalitis (latent that can reactivate) How to diagnose nipah virus - ans- RT-PCR of throat swab, nasal swab, blood, urine , CSF useful during early infection
  • ELISA to detect antibodies (IgM), useful late in infection and for past
  • MRI looking for lesions of white matter How is nipah virus currently treated - ans- Treat symptoms (rest and fluids)
  • No vaccine What is monoclonal antibody therapy - ans- attaching drugs to monoclonal antibodies to target specific cell types in the body How to prevent contraction of nipah virus - ans- Do not consume partially eaten fruits
  • Boil juice's and sap from date palms
  • Reduce overcrowding on farms What causes brucellosis - ans- Brucella melitensis in sheep
  • Brucella abortus in cows
  • Gram - coccobacillus Where is brucellosis common - ans- Indonesia, Thailand, Vietnam, Malaysia and India