By Motia Amber
Malaria is a life-threatening disease. It’s typically transmitted through the bite of an infected Anopheles mosquito. Infected mosquitoes carry the Plasmodium parasite. When this mosquito bites a person, the parasite is released into the bloodstream.
Once the parasites are inside your body, they travel to the liver, where they mature. After several days, the mature parasites enter the bloodstream and begin to infect red blood cells Within 48 to 72 hours, the parasites inside the red blood cells multiply, causing the infected cells to burst open
The parasites continue to infect red blood cells, resulting in symptoms that occur in cycles that last two to three days at a time.
Malaria is typically found in tropical and subtropical climates where the parasites can live. The World Health Organization (WHO) stated that about half the world’s population were at risk in 2015.
There are four kinds of malaria parasites that can infect humans: Plasmodium vivax, P. ovale, P. malariae, and P. falciparum. causes a more severe form of the disease and those who contract this form of malaria have a higher risk of death.
Prevalence of malaria in Pakistan
About half of the world’s population lives in areas where people are at risk of getting malaria through the bites of infected mosquitoes.
Each year, about 250 million persons suffer from the disease and one million of them die, mostly African children under five years of age.
There is growing agreement on the best available prevention and treatment methods, and international organizations such as the World Health Organization (WHO) have set up ambitious objectives for a large-scale fight against malaria.
Human malaria infection was quite frequent in the study region, which is one of the hottest areas of Balochistan, Pakistan. In clinically-suspected cases of malaria, there was a high slide positivity rate. The high prevalence rate of P. vivax poses a significant health hazard but R falciparum also may lead to serious complications, including cerebral malaria.
The cross-sectional study identified malarial parasites in the blood slides of 6119 suspected malaria patients from July 2012 to June 2014 through passive and active case detection methods. SPSS 11 was used for statistical analysis.
Out of 6119 suspected cases of malaria, 2346 (38.3%) were found to be positive for malarial parasite on blood smear slides. Of these, 1868 (79.6%) cases were due to Plasmodium vivax infection, and 478 (20.3%) had P. falciparum. However, seasonal variation was also noted: P. vivax infection was the highest (n = 131/144, 90.9%) in November and the lowest (n=83/176, 47.1%) in October. The prevalence was higher (n=1831, 78%) in males. Age-wise, the prevalence of the disease was 81.2% (n=334) and 80% (n=860) for age groups 1-10 years and 11-20 years. No case of P. malariae and P. ovale was detected in the study period. No association was found between types of infection and age groups.
Natural history of Malaria
Natural History of Disease is a key concept in Epidemiology. It signifies the way in which a disease evolves over time from the earliest stage of its pre-pathogenesis phase to its termination as Recovery, Disability or Death, in the absence of treatment or prevention.
Following the infective bite by the Anopheles mosquito, a period of time (the “incubation period” goes by before the first symptoms appear. The incubation period in most cases varies from 7 to 30 days. The shorter periods are observed most frequently with P. falciparum and the longer ones with P. malariae.
Antimalarial drugs taken for prophylaxis by travelers can delay the appearance of malaria symptoms by weeks or months, long after the traveler has left the malaria-endemic area. This can happen particularly with P. vivax and P. ovale, both of which can produce dormant liver stage parasites; the liver stages may reactivate and cause disease months after the bite of the infective mosquito. Such long delays between exposure and development of symptoms can result in misdiagnosis or delayed diagnosis because of reduced clinical suspicion by the health-care provider. Returned travelers should always remind their health-care providers of any travel in areas where malaria occurs, during the past 12 months
The classical (but rarely observed) malaria attack lasts 6-10 hours. It consists of:
- A cold stage (sensation of cold, shivering)
- A hot stage (fever, headaches, vomiting; seizures in young children)
- A sweating stage (sweats, return to normal temperature, tiredness)
Classically (but infrequently observed) the attacks occur every second day with the “tertian” parasites (P. falciparum, P. vivax, and P. ovale) and every third day with the “quartan” parasite (P. malariae)
More commonly, the patient presents with a combination of any the following symptoms: fever, chills, sweats, headaches, nausea and vomiting, body aches, and general malaise.
Immigrants and refugees made up the second largest patient group, with an overall proportion of about 20%. In Norway, Italy, France, Spain and Denmark they accounted for even more of the cases. The fact that more than 40% of the immigrants had contracted the disease on a visit to their former home country reveals that even those who may have lived in Europe for many still contribute considerably to malaria importation.
It seems peculiar that Western Africa was found to be a major region of infection, accounting for more cases than Eastern Africa. P. vivax prevalence was reported to be very limited in Western Africa, due to the presence of Duffy-negative blood-group variants
Analysis of the course of the disease revealed that half of the patients fell ill later than 60 days after arrival from an endemic area. The most common complaints were fever, headache, fatigue, and musculo-skeletal symptoms. The finding that symptom onset was significantly delayed in patients with chemoprophylaxis is consistent with recently published findings.
No fatalities and only few severe clinical complications were reported, which emphasises P. vivax’s limited virulence as compared to P. falciparum. More than half of the patients received in-patient treatment, indicating differences in national treatment policies rather than severe disease, since hospitalization rates varied greatly among TropNetEurop member countries.
Preventive measures to control Malaria
The control of malaria involves control of 3 living beings and their environment. Man, the host is a moving target and can take the disease with him to far and wide. Mosquitoes are moving, highly adaptable and have shown resistance to insecticides. It is therefore important to target non-flying eggs and larvae. The parasite also is highly adaptable, hides in humans and mosquitoes and has also developed resistance to drugs. Therefore, for effective malaria control, target man first, control mosquitoes next and keep trying to tackle the parasite with development of effective drugs and vaccines.
Man, the Host: Treat the affected, protect the unaffected. Problem are compliance, accessibility and availability of treatment and protective measures, mostly due to poverty and backwardness.
Parasite, the Agent: Ensure full treatment; kill the asexual forms and prevent the progression of disease, kill the sexual forms and prevent the spread to mosquitoes. Problem is Drug resistance
Mosquito, the Vector: Prevent breeding, prevent entry into houses, prevent bites to humans. Problems are resistance to insecticides and compliance by humans
Man’s Role in Malaria Control: Man is the most important link in the malaria control chain. He can be made to understand the problem and he can help in breaking the chain at multiple points. Therefore great emphasis should be laid on educating the people about malaria and its control, so that common people can effectively contribute in controlling this disease. This includes education of doctors about the need for early diagnosis and prompt treatment of malaria.
- Early diagnosis and treatment – treat early to reduce parasite load, hence spread; prevent deaths
- Treat completely to prevent spread and relapse
- Ensure compliance with complete treatment
- Personal Protection- prevent malaria by using bed nets, insecticide sprays etc., and by chemoprophylaxis.
- Seek his help in mosquito control
Strategies to overcome malaria
The WHO recommends strategies on how to prevent malaria transmission by controlling the mosquito population and on how to diagnose and treat malaria infections.
There are two main prevention methods:
- Protective bed nets treated with long-lasting insecticides prevent bites from malaria-infected mosquitoes and kill them.
- Spraying the inside walls of houses with insecticide is an effective way to kill large numbers of mosquitoes.
To be more effective, in high-risk areas (i.e. with one or more new malaria cases per 1000 inhabitants per year), these methods can be used together or be complemented, when needed, by other methods such as the management of mosquito breeding sites in order to reduce the larvae population.
The anti-malarial treatment recommended by the WHO aims to cure cases quickly before they become more serious, to protect unborn children, to avoid drug resistance and to prevent malaria in travellers. It includes the following recommendations
- Only people in whom laboratory blood tests confirmed the presence of malaria should be treated with anti-malarial drugs. However, in high-risk areas, children under five years of age with malarial symptoms should be treated straight away.
- Malaria has become increasingly resistant to drugs and, at present, medicines based onartemisinin are the only recommended treatment measures against Plasmodium falciparum,
- People with severe malaria should be treated immediately and then transferred to a health facility where they can get full treatment and care.
- Effective diagnosis and treatment should be of good quality, affordable and available at all health facilities.
- Pregnant women in high-risk areas should be given suitable anti-malarial drugs at least twice during the second and the third trimester of pregnancy, and three times if they are also HIV positive.
- It is important to monitor how effective the treatment is and to identify any possible development of drug resistance, any adverse reactions to medicines, as well as any effects on pregnant women and on pregnancy outcomes.
The writer is a student and researcher. She is currently studying Bachelor of Science in Nursing from the University of Lahore.