What is the reason for the epidemic of severe Plasmodium vivax malaria in East Africa?
Malaria is one of the health problem in Asia, africal and latin America.
The most common types are plasmodium falciparum, Vivax, Malaiae and Ovale. The Falciparum is the most complicated severe type than other milder types.
Vivax is the common type of sub-Saharan Africa and its magnitude affected by a variety of factors , poverty, the malaria vectors, climate conditions, drugs and resistanc and human immunity.
I agree with Gamal, it is about the local malaria vectors in the area. The vectors are the ones that are responsible for the transmission. I don't see the link between hygiene and an increase in prevalence of vivax malaria....
Probably the single most important factor will be the presence of the vector (mosquito) in large numbers. Control of the vectors will almost always result in a decreased incidence of the disease.
Overcrowding of villages, habitations without adequate measures to control breeding places for mosquitoes could also result in outbreaks with persistence of the infection.
Insecticide spraying along with other precautions like appropriate mosquito nets, mosquito repellents, body creams (containing di-ethyl toluamide, etc.) and introduction of bio measures such as larvivorous fish, e.g. Gambusia spp., may all help in controlling the problem
Resistance (if any) patterns to available to treatment should be considered when treating. Radical cure (i.e. use of primaquine) is another option.
Blood smear reports on the incidence of gametocytaemia should also give you an idea of transmission rates and the need for primaquine to completely stop transmission.
It is at best a very vague answer to your question. In my country (India) we have had and continue to have problems with malaria. We at one point of time actually thought we could eradicate it. We pretty much soon enough realised it was not possible and so we have just tried to control the problem through multi-pronged campaigns, the most important of which are vector control.
I hope this helps.
Regards,
Michael.
Earlier Plasmodium vivax was never considered responsible for severe malaria though relapses were common. However, of late, severe malaria cases due to Plasmodium vivax are on the rise in South-east Asian countries and elsewhere. I wonder whether it is changed strain(s) of P. vivax that are causing severe malaria not only in Africa but elsewhere as well
It may be due to late detection, like here in Zambia where almost 96% of malaria cases is due to plasmodium falciparum, and the rapid tests are specific to detect on p.falciparum its possible a person with another strain other than falciparum would test negative.
I think P. vivax and P. falciparum may have co-existed in Africa all the time.
P. vivax is characterized by low density parasitaemia and when P. falciparum dominates the infection vivax could be overlooked by microscopists. However, the introduction of ACTs has lead to a reduction of falciparum malaria in sub-Saharan Africa which in turn made P. vivax more detectable.
dear all
coming from a country, the Netherlands, that faces continuous threat from the water we had to develop water management and by that way also could eradicate malaria -it existed here as well! draining swamps and lakes swept malaria out of the province of North Holland a century ago...
given that fact and the natural habitats of mosquitoes, it seems high priority for subtropical and tropical countries to direct communal funds for breaking the vicious cycle of breeding in poor areas due to insufficient drainage and sewage systems.
lack of hygiene puts the ball where it needs to be: on the playground of governance of public funds to combat the hygienic disastrous circumstances of many poor people.
when one sees the films of places where Ebola is rampant one cannot stop questioning why so many governments do not act in this way. taxes so political reform are required for funding public health measures which essentially are non medical: good sanitation takes the roots off insect vector behavior.
for the time being i act like doctors can only do: study the use of new therapeutic approaches. so I am repeating the previous malaria study in Ghana with chloroquine comparing homeopathic drugs in the form of comparison with co artem in Kenya. in the full consciousness that engineers and politicians should root out this disease instead of entomologists and doctors...
Dear Adam
Do you sure about your question basis that" vivax malaria is sever and epidemic in Africa?
As it is famous and has mentioned in almost references the dominant and sever malaria in allover Africa related to P. falciparum not to P.vivax. Do you accept it or not?
In addition prevalence of negative Duffy blood group in almost people act as an natural defense against vivax malaria in Africa. Am I correct?
Dear all
If according your research results a new strain of P. vivax is responsible for severe epidemic malaria it could be a very urgent condition and you should prepare a new protocol for control and send for health ministry. I think more research about the vector population and its epidemiology in this condition is very helpful.Biological control is highly recommended .
Dear Adam,
Please take a look in these 2 articles, it will help you to make a potential parallel between South America and Asia-pacific region.
Sincerely,
Fabio
Dear Adam,
Please take a look of the article we published early this year. It raise the question about how to measure severe malaria due to P. vivax mono infection and discuss some key specific concerns about why is wrong to use the same definition as P. falciparum and why some diagnostic criteria might induce an overestimation of the severe malaria events that must be addressed to make a proper measure.
https://www.researchgate.net/publication/261771664_Plasmodium_vivax_Hospitalizations_in_a_Monoendemic_Malaria_Region_Severe_Vivax_Malaria
Article Plasmodium vivax Hospitalizations in a Monoendemic Malaria R...
Dear Adam,
As noted by Abbas Ali Eskandarian, P. vivax is uncommon in most of sub-Saharan Africa, except in the Ethiopian region due to most people lacking the duffy red blood cell antigen (the receptor for P. vivax. Rarely, human infection with P. vivax in the absence of a duffy antigen has occurred (refer letter in link below), but this is considered very uncommon. I have not heard about this epidemic of virulent P. vivax in East Africa. I t would be helpful to knwo which countries are involved and the coimmunity wide prevalence of duffy antigen in those countries. I would consider the following if I were investigating such an outbreak; a) Has a new highly virulent strain of P. vivax entered the population recently? b) Is this a re-emergence of P. vivax in regions with previously very low prevalence (and therefore absence of immunity prior to this outbreak), c) are there factors relevant to the local population (such as starvation, massive iron supplementation programs, etc) that might effect the host's immunity to P. vivax, d) Has a strain of P. vivax emerged in this area that can better enter the human red cell via a receptor other than the duffy antigen? Perhaps this is a help. Note that an unusual number of travellers returning from Africa have P. vivax in the absence of local human infection. A letter to EID a few years ago suggested that it was probably endemic in local primate populations lacking the duffy antigen (http://wwwnc.cdc.gov/eid/article/18/10/12-0120_article). believe that there is merit to this theory, therefore a final area of investigation might be; has the local monkey population increased and/or are they dwelling more closely to human habitations in the area where this outbreak is occurring? If either of the latter are the case, is there a concomitant emergence of an epidemic involving a highly virulent strain of P. vivax in that population? I hope that this has helped, please me if I can help in any further way: r.bradbury[at]cqu.edu.au
I believe that it is related to the declining cases of falciparum malaria, Do you agree?
It might be, but that is very unlikely given that the reduction of P. falciparum is mostly related to the effect of the many interventions implemented in the region that are also efficient against P vivax. Epidemiologically, you will need to increase the population at risk (susceptible subjects ~ Duffy positives) as well as the population of mosquitoes that are efficient P. vivax vectors to close the malaria cycle. Both can be driven by migration, which occurs often and very intensively in some African regions. I do believe that this will offer you a partial answer to your question, although I'm afraid that the reality is far more complex than that. Africa offers a very favorable environment for vivax malaria transmission so once we have more subjects that are protected against it there is no reason to don't expect more P vivax malaria cases.
Please take a look at the following RG link.
Article Global Epidemiology of Plasmodium vivax
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