Malaria Case Study

Arlín Toro

Rafael Tosado

Cole Benton

Potential Courses Study Aspect Case Scenario Resources/Activity

Case1Malaria

prophylaxisand control

Case2Parasite-drug

resistanceand diagnosis

challenges

Case3Ecology of

the mosquito vector

•Gen. Biology•Intro. Ecology•Gen. Microbiology•Parasitology

•Gen. Biology•Microbiology•Parasitology •Bioinformatics•Genetics•Molec. Biology•Evolution

•Gen. Biology•Parasitology•Ecology•Evolution•Population Biology

Tempting familyvacation package

but no time for malaria prophylaxis

Aunt Milagros died of cloroquine-resistant malaria

in 1982.

Students collectingmosquitoes find

Anopheles in a non-endemic area for

malaria.

•Maps•Basic concepts •Malaria Life Cycle•Travelers info.•WHO, CDC, NIH

•Bol Wrkbench•Case it•NCBI•Plasmo DB•CDC, WHO, NIAID

•HIPRE•My World GIS•Transgenic mosquitoes

Student products: develop ilustrated materials to use w/ deaf people, five min. comercials on malaria prophylaxis, etc.

Malaria Case Studies

As he munched yet another piece of Christmas rice pudding Sebastián Román glanced about the gaily decorated room at his family. His brother’s children were busily, excitedly comparing the presents they had pulled from underneath their beds earlier in this celebratory Three King’s Day. Family, food, music, and the smell of ginger and cinnamon smoldering on the table and sending small fragrant wisps throughout the house made everyone happy. Not everyone, Sebastián thought as he noticed his father staring out the kitchen window, a deep sadness on his face.

“What is it? Why aren’t you happy?” Sebastián inquired, approaching his father and pulling back the curtain so he could look out at what his father saw.

“I’m OK,” he said. “ I was just recalling that when you were just a small niño, twenty years ago on this day, we lost Aunt Milagros. It’s the ginger smell, I guess, that does it, that makes me remember that sad, sad day. I loved my sister and I miss her deeply.”

“You never talked about what happened to her,” Sebastián said, putting his arm around his father’s shoulder. “What did happen?”

Mr. Román pulled his son toward the table where they would soon enjoy the Feast of Epiphany on this, the last day of their Christmas. They sat down.

“In a word, ‘malaria.’” Sergio Román told his son.

“Malaria.” Román repeated.

“It could have been anything. It happened, it took her from us and that was all that mattered. Still, I never really understood that disease.”

Talking seemed to brighten Mr. Román. He enjoyed talking to this son who had flown home to their family from his university in the United States to share the holidays. Sebastián was a man now, a man a father could talk with.

• “We hadn’t had malaria here in Puerto Rico for over twenty years when your Aunt Milagros died of it.” He went on, “She was using her teaching skills to educate children in the Amazon Chocó forest. Evidently she became infected on that trip and came home with the parasite already in her body.”

• Sebastián’s mother Maria sat down beside her husband. She knew precisely what he would be talking about so seriously on this day, but she pretended ignorance.

• “So, what are we discussing here?”

• “Aunt Milagros,” Sebastián answered

• “I should have known. Your father always, as I do, remembers your aunt’s passing on this day. Was he finally discussing it with you?”

“Yes, he told me about her missionary work in Colombia.”

Sergio continued. “She took her antimalarial drug Chloroquine as a preventative, but it didn’t help. I just don’t understand.”

“When she returned to Puerto Rico, she told us that she had had a fever the day before. The second day home here in Barranquitas she had it again. Then she had it again in two days after that. Your aunt insisted that the fever cycles were not, absolutely not, malaria because: ‘I took the drugs as required by the regimen exactly as I was supposed to.”’ Maria continued her husband’s story.

“I believed her. I still do.” Sergio said.

There was a brief silence, then Maria, her hands moving across her chest, said what she didn’t want Sergio to have to say again. “She died a few days later.”

Etiology and Epidemiology of Malaria

• Malaria is a parasitic disease caused by a protozoan that replicates within red blood the cells (RBCs). The parasite is transmitted by a mosquito. Endemic malaria happens mainly in tropical climates where the mosquito is normally found.

• Countries at risk are those where mosquito transmission is possible but not happening currently. Seasonal outbrakes (mainly in summer months) have been reported in places such as Switzerland, England and New Jersey.

www.who.org/en/www.who.org/en/

• More than 100,000 people of all ages die of malaria each year according to the World Health Organization (WHO). Malaria is the second most devastating infectious disease in the world after AIDS.

• In 1980 malaria was endemic to 11 countries in the world. Currently, malaria transmission by mosquitoes happens in 107 countries according to the WHO.

www.who.org/en/

Level 1 QuestionsBiology of Malaria

1. Which are the etiologic agents of malaria?

2. Which species of the mosquitoe is responsible for transmitting the disease?

3. Describe the parasite’s life cycle.

Online Resources on Malaria

CDC MalariaMedline Plus

NIH

Medline PlusTutorial

NIH

Malaria Triad: Genetics

& Genomics

WHO/TDR Malaria Database

Challenfes for the Diagnosis of Malaria

Red blood cells (RBCs) infected with Plasmodium falciparum become sticky and tend to adhere to the inner wall of blood vessels. Sequestred RBCs may not be evident in a smear of peripheral blood at the early onset of infection when the ammount of infected RBCs is low (low parasitemia).

Animated movie:sequetred Rbcs infected

With P. Falciparum(www.whei.edu.au)

Click hereview videos

Penetrate and Burst

• Microscopic identification of malaria in peripheral blood requires an experienced microscopist, especially at low parasitemias. Both thick and thin blood smears should be performed in microscope slides to assess parasitemia.

Thin smear preparationvideo demonstration:

(vet.upenn.edu)

Click here

Side of fingertip

QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture.

QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture.

Thin blood Smear

Thick blood smear deep view of blood

Sinle-layer of RBCsadapted from www.cdc.gov

Thick and Thin Blood Smears

Level 2 QuestionsMalaria Diagnosis

1. Establish a relationship between the plasmodium life cycle and the periodicity of the fever episodes.

2. When would be the best time to take a sample of peripheral blood for a smear?

3. Do antibody-screening tests detect DNA mutations in in Drug-resistant strains?

4. Design a PCR-based method for the identification of chloroquine resistant strains of P. falciparum?

Online Diagnostic Resource

• DPDx - CDC - Division of Parasitic DiseasesComplete Information on diagnostic methods for parasitic disease

Click hereAnd search on:

Malaria and Diagnostic methods

Malaria Evolutioln and Bioinformatics

• With the use of the insecticide dichlorodyphenyl-trichloroethane (DDT) and the drug chloroquine, malaria was eradicated from most urban areas around the world in the 1950s. Since the late 1970s the parasite began to develop resistance to chloroquine and the mosquito developed resistance to DTT.

www.cdc.gov

• There are different mechanisms of resistance related to different anti-malarial drugs.

• Resistance to chloroquine and mefloquine in P. falciparum arose simultaneously in the early 1980s in South America and South east Asia.

• Mutations in the pfmdr gene have been associated wit multi-drug resistance. This gene encodes a trans membran-efflux pump.

Malaria basics

CDC MalariaMedlinePlus

NIH

MedlinePlusTutorial

NIH

Malaria Triad: Genetics

& Genomics

WHO/TDR Malaria Database

Level 3 Questions

• Using bioinformatics tools, find the protein sequence with higher similarity to the Plasmodium falciparum mdr.

• Based on the sequence alignments of the mdr protein find potential differences in the structure responsible for drug resistance.

• P. falciparum is more virulent than the other species that cause malaria in humans. Can this be explained in evolutionary terms? Compare the mdr protein sequence from different Plasmodium species.

Retrieving protein sequencesfrom NCBI Protein Data Bank

Retrieving protein sequences

• Click on the NCBI link on the right side.

• Search for Plasmodium falciparum mdr

• Select Protein: sequence database

• Establish limits (ref seq) Change the display mode to FASTA

NCBI

•Write your keyword

Plasmodium•Click go.

Click on Protein: sequence database

•You will obtain an incredible number of matches.•Let’s type Plasmodium falciparum.

Notice the number of hits is lower.Let’s try adding mdr (multidrug resistance) and click go.

•Now you got only 19 hits.•Click on limits to look for curated data

•Select from this pull down menu RefSeq.•Click go

•This is your accession number, write it down. You will need this number if you need to retrieve this number.•Click on the accession number

•The first part of the record consist of general protein information.

•This number is the accession number of GenBank. If you click on it you will be directed to the gene sequence.

•When you scroll down the record you will find information related to the protein function.

•The last part of your record is the protein sequence.•Now, let’s compare this protein with other known proteins.

•Click on Blink

•Select from this pull out menu FASTA.

•Click on best hits

•To view the structure of

•Select sort by taxonomy proximity•Observe that your list order is different

•Click select GI list

•Select the sequences the first two sequences.

•All the sequences that you selected will appear in this format

•Select from this pull down menu send to file•Save it

In this part you are going to work with Biology Workbench

Biology Workbench

Biology Workbench

Tutorial

If you have no experience with Biology workbench click on the Tutorial, complete the tutorial before you start with this unit.

If you just want a quick review you may proceed to the next part.

• Biology Workbench its free but you have to open an account.

• Select the Biology Workbench link.

BiologyWorkbench

•Register to create an account in Biology Workbench.

•Enter the Biology Workbench.

•Scroll down to the button of this page.

•Select the session tools.

•Select start new session from the pull out menu.

•Write down the name of the session.•Click on the Start Session button

•Select Protein Tools

•From the pull down menu select add new protein sequence.•Click on run button.

•Browse your sequences•Click to upload the file

•Click on save

•Click on save

•Click on both sequences

•On the pull down menu select CLUSTALW•Click on Run

•Accept all the parameters by clicking on submit button

•Scroll until you see the sequence.•Compare your sequences. •Check on the key colored legend.•Compare in terms of identity

•Click on import alignments

•First, select your alignment•Second, select on the pull down menu TEXTSHADE•Third, Click on Run

•Click on submit button

•Your results will be in this format which is easier to analyze.