Why is there no malaria problem in the US?

We’ve got plenty of mosquitoes here to act as vectors, and we’ve got areas like Florida and Hawaii that are fairly tropical in climate. I read the article on Wikipedia (yes, lame research, i know) about malaria, and it simply showed a map of countries that have a problem with malaria that excluded the US, but did not explain why. Why is it that malaria dominates sub-Saharan Africa, with a small amount of distribution in other tropical countries, but is virtually non-existent here?

Do the mosquitos that carry malaria (I believe there’s one basic type that carries it) do well in the U.S. climate? That I don’t know.

However, in most of the U.S., people have more access to screened doors and windows, air conditioning and bug repellent than they do in sub-Saharan Africa.

Note that malaria is not transmitted by just any mosquitoes, only a certain kind that prefers to live near human habitations. It was eradicated in the US by the late 1940s due to an intensive health campaign. Before that malaria occurred frequently even in northern cities. Getting rid of standing water in urban areas and fumigating against mosquitoes were a big part of it.

Malaria was essentially eradicated in Panama City and the Canal Zone as part of the construction of the Panama Canal in the early 1900s. These areas have been malaria -free ever since. Panama still does have some malaria, but only in remote areas.

From the CDC…

I just wanted to pop in and note that this is exactly the motivation why I wear a condom.

Not that I get laid that much, but jeez, the last thing I need is malaria from the hooker on the corner. :smack:

You don’t have to get malaria from a hooker. I contracted (caught?) malaria when I went to India.

I had a quick opportunity to go, as in a few days. We got the quinine but you have to start taking it 10 days to 2 weeks before you get into the foreign country for it to work. So I must have caught it right when I got there, but the incubation period is amazingly long, so I got sick right when I got back 1.5 months later.

No American doctor could diagnose it, and I went to 5-6 different ones. Eventually we had to go to an Indian doctor.

I also couldn’t donate blood for some period after that.

Thanks for the info, Scruloose and Colibri.

A follow-up question: how would mosquito-to-mosquito transmission occur? Would mosquito larvae from an infected mosquito become infected mosquitoes themselves? Or are mosquitoes born without malaria and only infect humans after they have been infected after biting a human with the disease?

Not to hijack my own thread too much, but have the rules for blood donation changed recently? A good friend of mine caught malaria while he was in Kenya and he was told he could never donate blood because of it. He could have been mistaken, i suppose, but that would be a bit unusual for him.

Interestingly, the Greek word ‘anōphelēs’ means ‘useless’. Definition of ‘anopheles’ at answers.com.

According to the CDC, mosquitos only get it from humans:

Indeed. One of the reasons the French attempt to build the canal failed in the late 1800s was malaria.

I’m guessing you’re joking, but the only way to get it from a hooker is if the mosquito bit her first, and then bit you. And I don’t think a condom would cover enough of your body to give you much protection from that. Humans can no more get malaria directly from other humans than mosquitoes can get it from other mosquitoes.

Even so, the mosquito would have had to have bitten her some time before, since the malarial parasite has to go through some phases of its life cycle inside the mosquito, and it would take time for them to migrate from the mosquito’s stomach to its salivary glands.

One reason that malaria can be eradicated by intensive campaigns is that it has no non-human reservior in other animals. Once you break the chain of human to mosquito to human transmission, you get rid of it.

That seems excessive. The American Red Cross guidelines about blood donation say:

I believe the parasites can persist in the body for some time, hence the 3 year waiting period.

The World Health Organization has this to say about ending malaria epidemics.
FAQ from – http://www.rbm.who.int/cgi-bin/rbm/rbmportal/custom/common/rbm/page.jsp?page=/custom/common/malariaFAQ.jsp#dieout
Geographically, where has Malaria been known to occur?
The boundaries of malaria transmission are determined by the presence and abundance of anophelines, their susceptibility to malaria infection, the type of hosts they select for blood meals, and whether they live long enough to serve as effective transmitters of infection, which in turn is largely determined by ambient temperature and humidity. Although currently largely confined to what today would be considered tropical conditions, in the past, malaria (P.malariae and P.vivax) was epidemic as far north as Finland.
What has caused Malaria epidemics to end in past occurences?
Malaria epidemics, if uncontrolled, follow a natural course:

The epidemic grows in a series of steps representative of the incubation interval (the period between the occurrence of infective gametocytes in the primary case and their reappearance in a secondary case), which is about 20 days for P.vivax and 35 days for P.falciparum. The length of the incubation interval and the degree of the reproduction rate determine the rate of multiplication of transmission, which is much faster in P.vivax epidemics than in those due to P.falciparum. In areas where both P.vivax and P.falciparum are present, the initial stages of an epidemic will thus be determined by a predominance of P.vivax infections and a very gradual increase in severity of the epidemic, while in later stages P.falciparum is likely to be abundant.
The peak of new infections due to a P.falciparum epidemic will only be reached when roughly 50 percent of the population at risk is infected, unless climatic changes (notably colder temperatures) prevent further transmission.
Control of a malaria epidemic involves relieving the immediate clinical consequences, preventing the progress of the epidemic (in time and space), and preventing future recurrences of the epidemic. This means improving disease management and providing some form of transmission control.

What are the conditions that would lead to a major epidemic?
Epidemics occur when non-immune and partially-immune populations are exposed to high rates of innoculation. Potential epidemic situations can to a large extent be identified by combining some basic knowledge of the malaria situation in an area with general aspects of the geography, history and socio-economic situation. Potential epidemic situations include:

areas of unstable malaria where conditions for malaria transmission are marginal in terms of altitude, rainfall patterns or temperature
areas where the level of endemic malaria has been reduced and the malaria situation has become unstable after mass drug administration and/or vector control programs, which can no longer be sustained
situations where non-immunes migrate into an endemic area. This would include refugee movements, and migration of labour forces into endemic areas
situations where persons harbouring malaria parasites migrate into a non-endemic, but receptive area. Receptivity refers to an abundant presence of anopheline vectors and/or the existence of other ecological and climatic factors favouring malaria transmission.
The size and impact of potential epidemics can only to a lesser extent be foreseen. Insufficient coverage of the population by health care services will exacerbate the impact.

In situations where a potential for malaria epidemics has been identified, responsible health services should be prepared to counter a beginning epidemic rapidly. Updated contingency plans should be at hand. At present many epidemic prone situations will, by their nature, stretch across national boundaries. Effective inter-country collaboration and sharing of experiences are paramount in developing emergency plans and preparing for adequate epidemic control measures.

How can Malaria be controlled?
The goal of malaria control is to prevent mortality and reduce morbidity and social and economic losses, through the progressive improvement and strengthening of local and national capabilities. Four basic technical elements of the malaria control strategy are:

to provide early diagnosis and prompt treatment
to plan and implement selective and sustainable preventive measures, including vector control
to detect early, contain or prevent epidemics
to strengthen local capacities in basic and applied research to permit and promote the regular reassessment of a country’s malaria situation, in particular the ecological, social and economic determinants of the disease.
Effective implementation of the malaria control strategy requires:

sustained political commitment from all levels and sectors of government
malaria control to be an integral part of health systems, and be coordinated with relevant development programmes in non-health sectors
communities to be full partners in malaria control activities
mobilization of adequate human and financial resources.

Yes, I was joking. I completely know that malaria is pretty much spread through 'skeeter bites, and I’ve got mefloquine and other anti-malarial pills (from my deployment) to keep me safe. That still didn’t prevent her from biting me to try to give me the disease though . . .

That’s the last time I go with the “cheap” hookers! :eek:

Careful with the lariam (mefloquine) - it can cause severe panic attacks and hallucinations. Rare, but something to be aware of…

Just a slight clarification.
While malaria isn’t a problem, in the US, there are isolated cases seen.
When I worked in San Diego we had two cases.
Neither person had been out of the state in the previous several months. They lived within a mile of each other.
There was a swampy area close to where they lived.
I don’t remember what agency did the investigation and irradication, but it was done very quickly and quietly.

Our squadron medic, who issued me the mefloquine, advised me to “avoid alcohol while taking this medication, an’ take it for 14 days after you get back to the States.”

I say to him, “Docko, I’m going to have so much alcohol in my blood the first two weeks, there ain’t nothing that’s gonna survive in it.” :smiley:

Take for fourteen days. Puhleeze. :rolleyes:

If I can nitpick, the WHO says that P. malariae, one of the four species of Plasmodium that cause malaria in humans, has a reservoir in chimpanzees and gorillas. So Tripler might want to avoid them as well.

If you were bitten by a cheap hooker, malaria wouldn’t be the first thing I would worry about . . . :eek: :eek: :eek:

Since I know you are in the military, I figured you would know about the actual means of transmission, but not everyone would have known you were joking.

Thanks, I wasn’t aware of that. I’m most familiar with the situation in the New World, where presence in animals, even monkeys is not a concern. This is different from Yellow Fever, for example, in that there is always a potential reservoir in the monkey population.