Parasites Part 2

Question 1

Define trichomonas

Question 2

Acanthamoeba

Question 3

Taenia

Question 4

Giardia

Question 5

Cryptospordium

Question 6

Enterobius

Question 7

Toxoplasma

Question 8

Last one here from first page

Question 9

Malaria

Answer 9

Parasite infection transmitted by mosquito bites
female Anopheles mosquito

Four main types of human malaria
Plasmodium falciparum
P. vivax
P. ovale
P. malariae

Question 10

Bilharzia

Question 11

Sleeping sickness

Question 12

Describe the malaria life cycle

Answer 12

Question 13

Epidemiology of malaria

Answer 13

Around 241 million cases of acute malaria in 2020

Estimated 627,000 deaths in 2020

Question 14

Who is at risk of malaria?

Answer 14

Almost 50% of the world’s population is deemed “at risk” dependent on where they live.

96% of malarial deaths occur in Africa – where P. falciparum predominates

One of the leading causes of death in the under 5s in Africa and 80% of all malaria deaths in Africa are in under 5s

Question 15

Has there been any cases in the UK?

Answer 15

Yes!
South East Kent a case of malaria was found and known as swamp fever. It was a milder form of malaria.

Question 16

If the habitat is knocked out, the mosquito cannot behave as a vector for the mosquito. Which environment do they thrive in?

Question 17

Signs and symptoms of malaria….

Answer 17

Onset: 9-14 days after the bite

Fever, headache, vomiting and other “flu-like” symptoms

Untreated becomes rapidly life-threatening

Anaemia

Cerebral malaria – severe complication of P. falciparum infection

Typically presents with periods of acute illness followed by periods of remission

Question 18

How is malaria diagnosed?

Answer 18

Smears of blood are stained with Giemsa stain and examined microscopically

[Giemsa stain is ???]

Thin and thick blood smears.

Thick to see how many of the blood cells are ? check this @ 12:26.

Thin film to see the level of infection and what proportion of cells are infected.

Some newer methods are:
Antigen detection kits
Molecular technology-based kits
Serology

Question 19

How is malaria treated?

Answer 19

The majority of drugs are active against the stage when the parasites are in the blood

Quinine in tonic water (quinine itself is still used)

Other quinoline drugs: antifolate drugs, artemisinin-based drugs (from the wormwood plant)

A problem with all monotherapy (one drug) as resistance may arise.

More than one drug prevents resistance.

There is resistance to treatments now.

WHO advises that combination therapies should include an Artemisinin-based drug

Question 20

Epidemiogical map for malaria

worldwide

Answer 20

Question 21

Epidemiological map

UK

Answer 21

Question 22

How can it be prevented?
[ABCD]

Answer 22

Awareness
Education of travellers to endemic areas.
The longer you are in a malarial region the higher your risk.

Bites

Prevent and avoid
Insecticide treated bed nets are effective but these can be out of reach for many financially.

Mosquito’s bite at night time so bed nets are so effective.

Significantly reduces the risk of acquiring the disease (also protects against other diseases transmitted by biting insects!)

Comply/Chemoprophylaxis
Encourage compliance with prescription of appropriate chemoprophylaxis
Balance the risk of malaria with the risk of adverse drug reactions
Needs to be started about a week before travel and continued for some four weeks after return to the UK

Diagnose
Particularly important to those who may need to self-medicate

Question 23

Vaccines

Answer 23

There is a vaccine available for children who live in the endemic areas which is given once when young.

Question 24

Prophylaxis

Answer 24

•Drugs used for prophylaxis include•Mefloquine (Lariam)•Atovaquone plus proguanil (Malarone)••Travellers to very remote areas may also take emergency stand-by treatment with them••Long term travellers may have to switch to a different drug after a stated time period

Question 25

What is the cause of “Sleeping Sickness”

Answer 25

Trypanosomiasis a eurokaryotic parasite.

Question 26

What is sleeping sickness?

Answer 26

* Three forms of geographically distinct sleeping sickness••American trypanosomiasis (Chaga’s disease)• * Two distinct forms of **African trypanosomiasis** **Gambia and rhodesia**

Answer 27

Gambia is chronic long lasting and Rhodesian is rapid acute infection.

Question 28

What is the vector for sleeping sickness

Answer 28

The Tsetse fly carries this parasite. Active in the daylight. Common in rural areas.

Question 29

Life cyrlce - blood, spinal fluid, bitten by anothet fy and life cycle continues…..check this at 12:41

Answer 29

Question 30

How is the situation improving

Answer 30

Controlling the fly and decreasing the animal reservoir.

Question 31

Signs and symptoms

Answer 31

•Early Phase: “flu-like” illness with fever, headache, joint pain, fatigue, restlessness••Neurological Phase: confusion, disturbance to senses, poor coordination, disturbance of sleep pattern.••Untreated, often fatal

Question 32

DX

Answer 32

Visualisation of the parasites with microscopy in blood or lymph dependent on which version of the paraiste it is. •in the blood (rhodesiensi infection)•in lymph node fluid (gambiensi)

Question 33

Treatment is unpleasant :( as chemcial heavy. Diagnosis is ESSENTIAL.

Answer 33

•Treated early, recovery is good; second stage is harder to treat, with more toxic agents••There are limited drugs and all have some side-effects••The drug regimes are also strict and require enforcement Used to be only admin by UV but now there is an oral treatmtn since 2019 (check this?)

Question 34

**Schistosomiasis** **An unusua vector/reservoir**

Question 35

Unusual complex life cycle which makes them difficult to target. Different life stages affect differnt treatments.

Answer 36

•Common name for Schistosomiasis is **Bilharzia**••Caused by a parasitic worm that infests various parts of the body – different species of ***Schistosoma***••People are infected by contact with contaminated water during activities such as swimming, paddling, washing and laundering••Has the second highest socioeconomic impact of any parasitic disease, after malaria Comes into contact through **being in water.**

Question 37

The life cycle of shisto….

Answer 37

Question 38

Shistasommmayeasis

Answer 38

Shape shifting parasite. Grows and changes form. Can live in water, snails and people. Start as eggs in fresh water lakes and rivers. After few hours they hatch and become miracidia. These sniff out special snails and take up home. They change shape again and mutliply x 100. Out of the snail they are cercaria and are thinner. They shoot through the water hunting for the next burrow: PEPLE!!! They burron through the skin into blood vessel They travel through bdy and transofmr into the a WORM - they pair up and then create lots of eggs which create the damage: can lead to organ damage. Eggs can come out of urine and start the life cycle all over again :(

Question 39

How are scientists working to get rid of schisto?

Answer 39

See the museu video on it parasites in motion: schist YouTube.

Question 40

Epidemiology od Shcisto

Answer 40

•74 endemic countries••est. associated deaths range from 24,072-200,000 per year••at least 236.6 million people required preventive treatment in 2019••90% of cases occur in Africa

Question 41

What is the reservoir animal for schisto?

Answer 41

•*Bulinus globosus*, the **intermediate host snail** for *Schistosoma haematobium*••Other species of snail harbour other species of *Schistosoma*

Question 42

Special features of worms of schisto

Answer 42

The worms can persist for years and avoid immune system and create 100's of eggs which get lodged in various areas in the body :(

Question 43

What does the clinical picture look like for schisto?

Answer 43

•**Urinary Schistosomiasis:** blood in the urine, urination is painful è progressive damage to the urinary tract è bladder cancer develops.••**Intestinal disease:** the liver and spleen become enlarged, intestinal damage è person becomes progressively weakened due to progressive damage to the liver, spleen and digestive tract.

Question 44

DX1

Answer 44

•Diagnosis of advanced infestations is largely clinical – the patient will have visually distended abdomen and signs of spleen and liver enlargement.

Question 45

DX2

Answer 45

•Diagnosis of early/mild infections is by demonstrating the presence of the parasites eggs in the urine or faeces of a patient. The urine appears red. The whole village MUST be treated as they would be using the same water source.

Question 46

TX and Prevention of schisto

Answer 46

•**Praziquantel**: effective in a single dose against all species of *Schistosoma*••Prevention methods include•Control of the snail population•Provision of safe, adequate water supply and sanitation•Health education – particularly regarding the risks of using local natural water supplies for bathing and laundering ••Using prawns to prey on snails:•[http://www.bbc.co.uk/news/science-environment-38571937](http://www.bbc.co.uk/news/science-environment-38571937) Sokolow *et al*. (2015) *PNAS.* 112(31), pp. 9650-9655 The water source MUST be clean and cleared of snails. Tehre Theere is one dose of tx but if the water source is not cleaned, there's is no point.

Question 47

How can we prevent parasitical infection?

Answer 47

Protect the community: Insecticide spray to kill the vecotr. eg Mossies like swamp like environment but even in tyres that have been transported this can carry the vector - using insecticide will erradicate the mosquitos. Protect ourselves: Insecticide treated bedding nets. Stay away from fresh water sources.