9. Travel Related Infections Flashcards

Question

Vaccines to prevent Salmonella infections

Answer 1

A polysaccharide vaccine based on the purified Vi-antigen (Vi-PS vaccine). • This single-dose intramuscular or subcutaneous injectable • Protective efficacy 70% A live attenuated oral vaccine (Ty21a, made with attenuated S. typhi strain Ty2) • available in capsules • protective efficacy of 33-67% Do not give immunocompromised person a live attenuated vaccine – as it can multiply and cause the infection in them

Answer 2

``` – falciparum (most prevalent) – vivax (mainly in people who have come from asia) – ovale – malariae – knowlesii ```

Answer 3

Vector - female Anopheles mosquito

Answer 4

* Mosquito transfers sporozoites in its saliva into blood of humans * Reach liver cells and multiply asexually to give rise to merozoites. Merozoites are released from liver and infect red blood cells * Merozoites reproduce asexually in the red blood cells - first stage get an early ring form called the early trophozoite which grows to the late trophozoite stage and finally grows to the schizont. * Some merozoites enter the sexual cycle to produce gametocytes (male and female) which remain in the red blood cells * Gametocytes are taken up by mosquitoes when they feed on people The male and female gametocytes give rise to zygotes in the mosquito gut which develop into ookinete and finally oocysts which rupture releasing the sporozoites

Answer 5

• Patients asymptomatic from time of the original mosquito bite until approx a week later • Typical incubation period usually between 8 – 17 days for P falciparum, P vivax, and P ovale and 18 - 40 days for P malariae. • Initial symptoms of malaria are nonspecific and similar to the symptoms of a minor systemic viral illness – fever, headache, fatigue, muscle and joint pain, nausea, and vomiting

Answer 6

* Blood film x3 * FBC, U&Es urea and electrolytes, LFTs,liver fucntion tetss * Head CT scan if neurological symptoms

Answer 7

• Treatment depends on species – P. falciparum • Artesunate • Quinine + doxycycline ``` – P. vivax, ovale, malariae – Chloroquine with primaquine • Dormant hypnozoites (liver) – Can recur months-years later – Give additional primaquine ```

Answer 8

-This Giemsa-stained, thin blood film showing Plasmodium falciparum ring-forms, and gametocytes

Answer 9

* Impaired consciousness/coma * Prostration or sit up with assistance * Convulsions * Deep breathing, respiratory distress (acidotic breathing) * Circulatory collapse/shock, systolic blood pressure <70 mm Hg * Jaundice * Hemoglobinuria (high amounts of hemoglobin in the urine) * Abnormal spontaneous bleeding * Acute renal failure * Pulmonary edema

Answer 10

* Asia: majority subclinical * Mild infections: fever with headache * More severe infection: sudden onset headache, high fever, neck stiffness, stupor, coma, occasional convulsions and spastic paralysis * Vaccination recommendations are seasonal

Answer 11

* Transmitted between people by mosquitoes * Symptoms usually begin 4-7 days after mosquito bite and last 3 to 10 days • Epidemics occur when there is a concurrence of large number of vector mosquitoes, a large number of people with no immunity to 1 of the 4 virus types (DENV 1-4) - epidemica can occur in certain seasons

Answer 12

* Incubation 3-14 days * Majority asymptomatic or fever plus rash (2-5 days and later in infection) * Classic dengue: fever, retro-orbital headache, musculoskeletal pain, rash * Leukopenia, thrombocytopenia * Diagnosis clinical; also serology, PCR

Answer 13

– Rocky Mountain spotted fever (ticks carry Rickettsia rickettsii) – Crimean-Congo hemorrhagic fever (tick born virus) – Lyme disease (tick borne Borrelia burgdorferi)

Answer 14

* Caused by Rickettsia (Intracellular parasites) * Bitten by infected lice, mites or fleas found on small animals like mice, rats, cats and squirrels. People can also carry them on their clothes, skin or hair. •Symptoms – very high temperature (usually around 40C) – feeling sick, being sick – diarrhoea, abdominal pain – dry cough – joint pain, backache – dark spotty rash on chest that may spread to the rest of the body (apart from face, palms and soles of feet) •Diagnosis: PCR

Answer 15

---> Viral Hemorrhagic Fever (VHF) refers to serious illnesses caused by particular viruses. Viruses cause a lot of bleeding due to platelet reducation * Lassa fever (Lassa virus) * Crimean-Congo HF (tick borne virus) * Ebola (Ebola virus) * Marburg (Marburg virus)

Answer 16

• fever, fatigue, dizziness, muscle aches, loss of strength and exhaustion, vomiting, diarrhoea headaches, • Severe cases Internal/external bleeding at 5-7 days – bleeding under the skin, in internal organs or from body orifices like the mouth, eyes or ears. Some severe cases may also show signs of shock, nervous system malfunction, coma delirium and seizures. Spread by direct contact with body fluids

Answer 17

•Transmitted to people from wild animals (such as fruit bats, porcupines and non-human primates) and then spreads in the human population through direct contact with the blood, secretions, organs or other bodily fluids of infected people, and with surfaces and materials (e.g. bedding, clothing) contaminated with these fluids.

Answer 18

* a high temperature * joint and muscle pain, severe muscle weakness * diarrhoea, vomiting, a rash, stomach pain and reduced kidney and liver function can follow. * infection may then cause internal bleeding as well as bleeding from the ears, eyes, nose or mouth. •Vaccine in high incidence areas

Answer 19

* Schistosomiasis * Leptospirosis * Hepatitis A

Answer 20

3 species • Shistosoma mansoni • Shistosoma japonicum • Shistosoma haematobium * Parasite (blood fluke) penetrates human skin following completion of part of the lifecycle in snails * Migrate to blood stream * Katayama fever is the manifestation of acute Schistosomiasis * fever, an urticarial rash, enlarged liver and spleen, and bronchospasm * Mid East, Africa, Eastern S. America and Carribean

Answer 21

Leptospira interrogans * Water contaminated by animal urine * Incubation 7 to 14 days * Abrupt fever> 39oC, chills * Later invasion of liver, kidneys and CNS * Gives rise to jaundice, hemorrhage, tissue necrosis * Aseptic meningitis (inflammation of meninges without positive culture)

Answer 22

* HIV * Hepatitis B * Other STDS: herpes, gonorrhea, syphilis, HPV

Answer 23

• Classical spikes on the outer surface of the virus – resemble the “corona” of the sun. Envelope Protein capsid Receptors S protein = spike protein = target for treatments

Answer 24

* Named by ICTV (International Committee on Taxonomy of Viruses) * Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)

Answer 25

* Named by WHO in the ICD (International Classification of Diseases) * Coronavirus disease (COVID-19)

Answer 26

* SARS-CoV-2 is an enveloped β-coronavirus. * Has a genetic sequence very similar to SARS-CoV-1 (80%) and bat coronavirus RaTG13 (96.2%). * The viral envelope is coated by spike (S) glycoprotein, envelope (E), and membrane (M) proteins. * Host cell binding and entry are mediated by the S protein.

Answer 27

1. The first step in infection is virus binding to a host cell through its target receptor. • The S1 sub-unit of the S protein contains the receptor binding domain that binds to the peptidase domain of angiotensin-converting enzyme 2 (ACE 2) 2. Spike protein binds to ACE receptor 3. In SARS-CoV-2 the S2 sub-unit is highly preserved and is considered a potential antiviral target.

Answer 28

* Respiratory | * By touching a phomyte – thing that has covid on

Answer 29

* All human coronaviruses have animal origins (Natural Hosts). * Domestic animals can suffer from disease as Intermediate Hosts that cause virus transmission from natural hosts to humans. * Bats are likely reservoir hosts for SARS-CoV-2.

Answer 30

1. The virus binds to ACE 2, the host target cell receptor, which is principally expressed in the airway epithelial cells and vascular endothelial cells. 2. This leads to membrane fusion and releases the viral genome into the host cytoplasm. 3. Subsequent steps of viral replication, leading to viral assembly, maturation, and virus release.

Answer 31

Day 0 – when you start getting symptoms • But you have picked up covid before this • Following initial exposure, patients typically develop symptoms within 5-6d (incubation period) * The viral load peaks in the first week of infection, declines thereafter gradually * Virus does not cause illness, virus causes a disease response which causes illness The antibody response gradually increases and is often detectable by day 14

Answer 32

• MUTATIONS are errors that occur during the process of duplicating viral RNA. - changing RNA (changed rna may or may not impact protein)

Answer 33

Mutations produce VARIANTS which are similar but not exact copies of the original virus “PARENTAL STRAIN”.

Answer 34

* A new STRAIN is when a variant displays distinct physical properties to the original virus. * Changes look and function of virus

Answer 35

• A virus is essentially a microscopic box full of genetic material: – The box must be robust enough to keep the genetic material safe in the body and in the outside world. – But to infect cells, the box must open to let the virus's genetic material out. * Too stable, and the virus can not open up and infect cells efficiently. * Too unstable, and the virus can not survive for long after being transmitted

Answer 36

adapt to their surroundings and more effectively move from host to host. * Mutations can help viruses to better evade the host’s immune systems, treatments and vaccines. * Mutations can cause varients • A mutation can help the virus gain traits that enable it to reproduce quickly or adhere better to the surface of human cells. * Viruses can mutate so quickly that they do not develop traits that are advantageous to transmission. Hence some virus mutations seem to emerge and then die off. * Mutations can be beneficial or harmful

Answer 37

Spike protein ---> part of virus that latches on to the host cell to allow virus to enter a cell

Answer 38

• Spike proteins (S) on SARS-CoV-2 bind to receptors enabling the virus to enter the host. • A Spike protein is made up of 3 smaller peptides in the OPEN or CLOSED orientations. • The more that are open, the easier for the protein to bind. = stickier it is to bind Less needed to infect

Answer 39

• The D614G mutation is caused by a single letter change to the viral RNA code. This makes open conformations more likely, hence increasing the chance of infection

Answer 40

----> Pfizer-BioNTech BNT162b2 and Moderna mRNA-1273 vaccines

Answer 41

* Contain the genetic code (mRNA) of the spike protein. Once inside the body, the spike protein is produced, causing the immune system to recognise it and initiate an immune response. (doesn't actually contain the virus – so it doesn't cause covid) * If the body later encounters the spike protein of the coronavirus, the immune system will recognise it and produce antibodies to destroy it before an infection is caused. * These vaccines can not cause COVID-19 disease, as there is no whole or live virus involved. The mRNA is naturally degraded after a few days.

Answer 42

* Made from a virus that is a weakened version of a common cold virus known as an adenovirus. This adenovirus has been genetically changed so that it can not cause infections in humans. ChAdOx1 has been engineered to make the spike protein of the SARS-CoV-2 virus. * The immune system recognises the spike protein as foreign, forms antibodies and then attacks the SARS-CoV-2 virus, preventing an infection.

Answer 43

* Respiratory aerosols bind to epithelial cells in the upper respiratory tract. * Main host receptor is the ACE-2 (nasal epithelia++). * Local replication and propagation. * This stage lasts a couple of days. Limited immune response generated. * Despite having a low viral load, individuals are highly infectious, and the virus can be detected via nasal swab testing

Answer 44

• Non-specific symptoms- in first phase : Fever / Malaise / Dry, persistent cough. Cells involved have a lot of ACE receptors * Can cause transient damage to olfactory epithelial cells, leading to olfactory dysfunction. * Greater immune response generated during this phase (involving the release of C-X-C motif chemokine ligand 10 (CXCL-10) and interferons (IFN-β and IFN-λ) from the virus-infected cells. * The majority of patients do not progress beyond this phase as the mounted immune response is sufficient to contain the spread of infection.

Answer 45

• 1/7 or 8 of all infected patients progress to this stage and can develop severe symptoms.

Answer 46

1. Virus invades and enters the Type 2 alveolar epithelial cells - pneumocytes via the host receptor ACE 2. Undergoes replication to produces more viral Nucleocapsids. 3. The virus-laden pneumocytes now release many different cytokines and inflammatory markers “Cytokine Storm”: Interleukins (IL-1, IL-6, IL-8, IL-120 and IL-12), Tumour necrosis factor-α (TNF-α), IFN-λ and IFN-β, CXCL-10, monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1α (MIP-1α) 4. This ‘cytokine storm’ acts as a chemoattractant for neutrophils, CD4 helper T cells and CD8 cytotoxic T cells, which then begin to get sequestered in the lung tissue. (isolate and damaged lung tissue, making area inflammaed and sludgy) 5. These cells are responsible for combating the virus, but in the process they cause subsequent inflammation and lung injury. 6. The host cell undergoes apoptosis with the release of new viral particles, infecting adjacent type 2 alveolar epithelial cells in the same manner. 7. Sequestered inflammatory cells → Persistent injury → Loss of both type 1 & type 2 pneumocytes → Diffuse alveolar damage → ARDS acute respiratory distress syndrome

Answer 47

* No clinical symptoms | * Positive lateral flow / PCR test

Answer 48

* Fever / New, persistent cough / Olfactory dysfunction * Sore throat / Malaise / Aches * GI symptoms (N/V/D/Abd pain)

Answer 49

• Pneumonia symptoms without hypoxia

Answer 50

• Pneumonia symptoms with hypoxia (SpO2 <92%)

Answer 51

* ARDS * Shock * Coagulation defects * Encephalopathy * Heart failure * Acute Kidney injury

Answer 52

* Persistent high temperature – paracetamol doesn't decrease it * New continuous cough * Loss of change to your sense of smell or taste

Answer 53

* Approximately 80% of patients can be managed effectively at home with conservative measures for viral infection. * Remote assessment and risk stratification is a clinical dilemma.

Answer 54

– To support resilience in Primary Care – To provide a clinically safe and effective face-to-face assessment service for patients that can not be seen at their base practices due to the current coronavirus pandemic restrictions. – To stratify the clinical risk and offer appropriate management.

Answer 55

* Temperature * SpO2 before and after exertion * Blood Pressure * Chest auscultation * Resting Pulse * ENT examination * Respiratory Rate * Urinalysis as necessary

9. Travel Related Infections Flashcards

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