Potential Sources and Information on Malaria

 

On global warming and malaria:

http://whyfiles.news.wisc.edu/016skeeter/climate.html

text from this source:

Warmer = buggier?  The prospect that the globe will warm up due to increased concentrations of greenhouse gases (defined) in the atmosphere sends chills up the spine of specialists in mosquito-borne diseases. Greenhouse gases -- mainly carbon dioxide -- reflect heat back to Earth that would otherwise be lost to space.

Energy trapped in the atmosphere by the greenhouse effect. Map courtesy of Learning Through Collaborative Visualization Project at Northwestern, funded by the National Science Foundation.

The greenhouse effect -- the warming caused by this reflection -- made the planet inhabitable in the first place. But the carbon dioxide concentration is rising steadily each year, largely due to burning fossil fuels and clearing forests.

Within the last year, an international group of scientists warned that the warming seems to have begun. The average warming is predicted to range from 1 degree to 3.5 degree C by year 2100.

What's that got to do with our favorite bloodsucker?  Simply this: the existence and activity of mosquitoes and mosquito-borne diseases is strongly linked to temperature. In Zimbabwe, for example, the prevalence (defined) of malaria is determined by altitude, which in turn determines temperature.

But global warming may not just cause mosquitoes to proliferate; it may also allow malaria to spread. The malaria parasites cannot develop below the 16 degree C winter isotherm (defined). But if, as predicted, global warming raises winter temperatures more than summer ones, we could see a dramatic expansion of range for malaria. At least, that's the opinion of these folks.

The effect of global warming on dengue is no more encouraging, according to a recent journal article: "Slightly higher temperatures within the range of mosquito viability lead to more infectious mosquitoes that bite more frequently" (see Global Climate Change). Quick: tell me everything I need to know about protecting myself from mosquitoes.

 

Chloroquine resistance map (source of  chlor_resistance.gif):

http://www.ncbi.nlm.nih.gov/Malaria/ResProjects/MGS/CQRspread.html

           

On malaria: (an informative site):

http://www.who.int/inf-fs/en/fact094.html

 

Map of malaria distribution (malaria_distribution.gif):

            http://www.biosci.ohio-state.edu/~parasite/distributions/malaria_distribution.html

 

Source of these images:  ring_form.jpg (early trophozoite), compact_form.jpg   

      (growing trophozoite), band_form.jpg (growing trophozoite), schizont_1.jpg  

      (immature schizont), schizont_2.jpg (mature schizont), fem_gam.jpg (female  

      gametocyte), male_gam.jpg (male gametocyte);  note:  credit should be given to the

      Department of Parasitology, Faculty of Medicine, Chiang Mai University,   

      THAILAND

http://www.medicine.cmu.ac.th/dept/parasite/official/framepro.htm

 

            (an interesting database of images)

General infection info

     sporozite_1.gif (inside a mosquito's stomach; Sporozoites of

      Plasmodium; approximate length of each = 10 m.  This life cycle stage is produced  

      by the oocyst (see below), migrates to the mosquito's salivary glands, and is injected

      when the mosquito feeds); oocyst.gif

http://www.biosci.ohio-state.edu/~parasite/plasmodium.html

 

Anopheles.gif:  (female)

http://www.ent.iastate.edu/imagegal/diptera/culicidae/an-punct-f.html

           (a great database of bugs and stuff from Iowa State University)

 

History of malaria / general overview:

http://www.travelhealth.com/malaria.htm

  text from this source:

Cause:

                  Plasmodium Parasite - P. ovale, P. vivax, P. malariae, and P.

                  falciparum

 How Spread:

                  Bite of the Anopheles mosquito. This mosquito feeds from dusk to

                  dawn.

            Areas of Risk:

                  Throughout tropics, in mostly rural areas, in urban centers in

                  parts of Africa and Asia. Usually not a severe problem at higher

                  altitudes (above 2,200 meters, lower further away from equator).

                  See map, below.

Incubation period:

                  Falciparum 7-30 days, other strains up to a year. Inadequate

                  prophylaxis may cause malaria to lie dormant for up to a year.

Signs and Symptoms:

                  Sudden high fever, chills, muscle aches, headache. Many have

                  nausea, vomiting, and diarrhea. If not treated, symptoms may

                  diminish and recur over a prolonged period.

             Mimics:

                  Typhoid, dengue, flu, other viral or bacterial illness.

Treatment:

                  Chloroquine for forms other than "chloroquine-resistant P.

                  falciparum" (CRPF). CRPF treated with Lariam or Fansidar.

                  Those at risk in remote areas may carry a treatment dose of

                  Fansidar with them (if not sulfa-allergic)for use if they suspect

                  they have malaria - early treatment of falciparum malaria is vital.

             Significance  worldwide:

                  Huge problem worldwide, with hundreds of millions of cases

                  yearly, and over 1 million deaths per year - largely in African

                  childen. The parasite becomes resistant to newer treatment and

                  prophylactic medicines, and mosquitoes become resistant to

                  pesticides.

             Significance to Travelers:

                  Probably the most common serious imported disease. Easily

                  picked up by travelers, especially those with rural night-time

                  exposure - African Safaris the highest risk activity by far!

             Mortality rate:

                  As high as 2% with CRPF - representing the cerebral form.

                  Delayed diagnosis in malaria-free areas a contributor to mortality

                  rate. Generally falciparum is only form that is fatal.

             Prevention:

                  When exposure will take place, take an antimalarial medication

                  starting one to two weeks prior to exposure and continue for

                  four weeks afterwards. Appropriate medications include

                  chloroquine in areas without CRPF, or mefloquine ("Lariam") in

                  areas with CRPF. For those who cannot tolerate the Lariam (see

                  below - about 15% have side effects, usually headache, dizziness,

                  sometimes worse, such as depression) doxycycline may be taken

                  daily. This may promote yeast infections in women. The

                  combination of weekly chloroquine and daily proguanil is also

                  effective. Proguanil is not available in the US and must be

                  obtained overseas (where it is widely available). Avoid night-time

                  mosquito bites in high-risk areas! Be aware of mosquitoes and use

                  agressive repellents if mosquitoes are around. Bednets used at

                  night very helpful. Review section on insect avoidance!

           

Other recommendations:

                  There is no vaccine currently available (see below for a discussion

                  of the current malaria vaccine). Make sure good screening is

                  present where you stay, avoid night-time activities outside if

                  possible. Bednets very important.

  On traveling and preventing malaria (a good informative site--can also download the  traveling guidelines brochure from this site):

http://www.cdc.gov/ncidod/publications/brochures/malaria.htm

An interesting site on possible side effects of Lariam, a treatment for malaria--you might want to look at this:

http://www.travelhealth.com/malaria.htm

 

            text from this source:

  World Distribution of Malaria From Health Information for International Travel by the CDC

Doesn't Lariam Have Bad Side Effects?

The reality of life is that bad news travels much faster than good. While it is true that

there are obnoxious side effects from Lariam, most can take it without problems. Some

studies show that 85% have no problems with this medication. Of the other 15%, most

of the side effects are minor headaches and dizziness, some of which resolve with the

help of some acetominophen. A small percentage of those taking Lariam must

discontinue it due to side effects. My experience with about 40 employees of a mining

company that I have frequent repeated contact with because of their travels leads me

to agree with these figures. (Most of our regular travel clients do well and we never

hear from them after their trip.) Out of this number a few have minor side effects and

one simply cannot take it at all because he gets severe depression when he does. A

symptom such as this could be very serious if one did not recognize it as a side-effect

and continued taking the medication.

 

One survey published in the British Medical Journal reports more frequent severe

side-effects than previously appreciated. Hospitalization from side effects occurred in

about one in 650 lariam-users, and seizures in about one out of 1100. I think it is

important to determine the actual risk of malaria based upon your destination,

planned activities, and duration of exposure, and then decide whether lariam is an

appropriate drug for you. Alternatives such as doxycycline (if you are not pregnant)

do exist.

 

If you are very concerned with possible side effects, (for example, if you plan to scuba

dive and figure that an underwater seizure could prove fatal) one option is to either

start the tablets three weeks before your trip or even (some have suggested) take three

tablets spread out over the first week while at home - thus building up a "steady-state"

level before you leave. If side effects occur, they will probably occur at home, and you

would have time to discuss changing prophylaxis before you leave. Those pregnant or

with known disorders of electrical conduction in the heart, psychosis, seizure

disorders, or severe depression should consider alternative drugs (pregnant women

should probably avoid areas with CRPF!). Long-term studies of Peace-Corps volunteers

have shown that if you don't have side effects in the short term, you can most likely

take this drug for years without problems.

 

There is an organization in London and now in the US which provides assistance to

those who believe they have been harmed by lariam - "Lariam Action". If you would

like to contact Lariam Action, try: Lariam Action, 122 Balgores Lane, Gidea Park,

Romford, Essex RM 5JX England. The US branch is: Lariam Action USA, 1563 Solano

Ave., #248, Berkeley, CA 94707.

 

But Are There Problems?

  I think that Lariam causes more side effects than many drugs. Unfortunately, however,

malaria kills about a million people per year in the world, so the usefulness of Lariam

cannot be underscored. However, I have had some questions all along. The kinetics of

distribution and elimination of Lariam are complex and, I think, not very well

understood, even by Hoffman La Roche. Originally it was recommended on an

every-two-weeks schedule. Some Peace Corps workers in East Africa developed

malaria, and it seems they contracted it towards the end of the two-week period. The

recommendation to double the frequency to weekly was the result. Why not every ten

days? Might there be fewer side-effects? The other concern is that there is only one

adult dosage. My wife would be advised to take the same 250mg tablet weekly that I

would - even though I weigh about twice what she weighs! Evaluation of responses to

my lariam use survey show that weight, however, is probably not an issue.

 

I received an e-mail from Sheldon Johnston in Australia who also feels that Lariam is a

dangerous drug. His experience was of having bad neurologic side effects which began

as disorientation and weakness which went unrecognized and misdiagnosed by

physicians in Africa - he was treated for malaria and other things he did not have.

After having a seizure he made his way to London where the real problem was

diagnosed. This is an awful experience with lariam. This drug should be used

cautiously and with alertness for possible side effects. Starting it several weeks prior to

departure should be considered, and carefully weighing the risks of medication and of

getting malaria is vital. There are other means of avoiding mosquito bites, so for

minimal risk activities, repellents, netting, clothing, etc., can all be used. For nighttime

activities in Africa or prolonged stays, prophylactic medication is probably still worth

considering strongly. For us physicians, it is easier to make a recommendation than to

present the risk-benefit situation and let the patient make up their mind - and many

patients want to be told what to do... Where available I have put malaria statistics

under country risks to assist in this decision process. Unfortunately, these statistics are

several years old and not available for most of Africa, where the risk is highest, because

of inadequate disease reporting and monitoring systems. Mr. Johnson has just put

together a very informative website in which he discusses his own bad experiences and

has links to a large number of articles and sites both pro and con on Lariam.

 

Other sources of information include: The Malaria Debate, or The British Medical

Journal news , or Study confirms relative safety of mefloquine prophylaxis . Or simply

do a search through Yahoo or one of the other search services. Thanks to Mr. Johnston

for sharing this information and his unfortunate experience - if others have had bad

experiences with lariam or malaria please contact me.

 

The Really Bad News

 

Mosquitoes are developing resistance to more and more insecticides, and the

Plasmodium falciparum are becoming resistant to Lariam and proguanil. The newest

drug on the horizon, artemesin, and other derivatives of the artemesia annua plant

("sweet annie"), may offer a great deal of promise. Until an effective vaccine is

developed, it will be an increasingly vicious cycle...

 

Presumptive Treatment

 

If you are traveling in remote areas with falciparum malaria, especially if not taking

optimum prophylaxis, you might want to take along a self-treatment medication to

take if you think you have malaria (you would still want to get evaluated and head

towards a hospital or clinic). This would consist of Fansidar (if not sulfa-allergic - the

adult dose is three tablets taken together) or - if you are in Europe and can get it -

Malarone. Malarone is taken four tablets daily for three days.

 

What About the Vaccine?

 

Dr. Manuel Patarroyo of Colombia has developed over several decades of painstaking

research a malaria vaccine which has had some success in clinical trials in Africa. It

has been put down by much of the western medical community, and has not been put

into distribution. Is this western arrogance? While it is true that it is only about 30%

effective in preventing death from malaria, that is about the same effectiveness as

typhoid and cholera vaccine - and wouldn't preventing 30% of the million deaths per

year be pretty significant? Mr. Luis Guillermo Restrepo Rivas in Medellin, Colombia,

passed along some very interesting sites regarding the vaccine: One is a WHO article

on intellectual property rights, and who should have ownership to vaccines (Dr.

Patarroyo has donated rights to his vaccine to the World Health Organization).

Excerpts from a talk by Dr. Patarroyo where he discusses attitudes towards his

research is very interesting.

 

Let's keep the lines of communications open - part of the reason for this site is to share

information, and I was not even aware of such an organization in Great Britain, and

will look forward to hearing more from them. Even if I don't agree with everything

they say, people challenging those in powerful positions (such as pharmaceutical

companies) helps to keep them a little more honest... Looking at how Lariam is used,

and perhaps clarifying what is the right risk/benefit situations, will help all of us.

 

If you would like more details about malaria (or other tropical diseases) and current

efforts by the World Health Organization , the World Health Organization Division of

Tropical Diseases Home Page is a good resource.

 

(c)Travel Health Information Service - everything you need to know!

 

Dr. Stephen Blythe, Travel Health Information Service

 

 

A historical perspective on malaria:

http://whyfiles.news.wisc.edu/016skeeter/malaria1.html

 

            text from this source:

After years of decline, malaria is on the move, and despite the recent headlines given to the "catch-me-you're-dead" Ebola virus, it's malaria that counts its victims in the millions: the disease infects about 400 million people each year, according to the

World Health Organization. 

 

About 1,200 Americans are infected with malaria each year; most while traveling

abroad. The 1995 Michigan case was not the only recent infection in temperate

parts of the United States: in 1993, two people in New York City, which is at least

1,000 miles north of malaria country, caught the ancient illness from mosquitoes

that had fed on infected people in the area. Since the outbreak limited itself,

mosquito-control efforts were not needed (see Mosquito-transmitted malaria...).

 

But since anopheles (defined) mosquitoes live in the summer all over the United

States, there's a possibility that the disease could reestablish itself here. From

colonial times until well after the Civil War, malaria was endemic in parts of the

Mississippi Valley and Chesapeake Bay.

 

It's worse.  Still, malaria remains a tropical disease, and it's most severe in Africa, where, it kills 2 million people each year, either directly or with some help from acute respiratory infections. Most of the dead are children.

 

Four parasites, all in the genus Plasmodium, cause various forms of malaria.

Malaria expert Clive Shiff of Johns Hopkins University School of Hygiene and

Public Health, explains that Plasmodium falciparum is the most severe species since

it can infect any red-blood cell. P. falciparum can cause severe anemia and kidney

failure, or it can constrict small blood vessels and cause cerebral malaria. Either

problem can be deadly.

 

Although Africa is unlucky enough to be the focus of P. falciparum infection, the

species is also found in Southeast Asia and Latin America.

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