THE USE OF INSECTICIDE TREATED NETs AND INDOOR RESIDUAL SPRAYING IN MALARIA CONTROL
Malaria is a disease condition caused by a protozoan parasite of the genus plasmodium which is transmitted by female Anopheles species. Pregnant women and children under 5 years of age are the most vulnerable group affected by malaria. To control malaria, WHO recommended vector control strategy, among the vector control are insecticide – treated nets (ITNs) and indoor residual spraying(IRS) which are currently the preferred methods of malaria vector control. In many cases, these methods are used together in the same households, especially to suppress transmission in holoendemic and hyperendemic scenarios. Insecticide treated nets are safe for use as a personal protection method during pregnancy. Insecticide treated nets(ITNs) have been an effective intervention for preventing malaria transmission by reducing the chances that an individual would be bitten by an infective Anopheles mosquito. ITNs is a cost effective intervention to reduce child mortality and maternal anemia through sleeping under insecticide treated nets . ITNs reduce mortality and morbidity in children aged 1 – 59 months. LLINs reduce malaria mortality and morbidity at the community level in malaria endemic countries worldwide. IRS kills mosquitoes after they have fed if they come to rest in the sprayed surface and also prevents transmission of infection to other persons. Both insecticide – treated bed nets(ITNs) and indoor residual spraying(IRS) reduce malaria in high malaria transmission areas. Though widespread, there has been limited evidence suggesting that such co- application confers greater protective benefits than either ITNs or IRS when used alone. To ensure that the problem of insecticide resistance is avoided, the ITNs and IRS products should preferably be of different insecticide classes, e.g pyrethroid – based nets combined with organophosphate or carbamate based IRS.
TABLE OF CONTENTS
Title page i
Approval Page ii
CHAPTER ONE: Introduction 1
CHAPTER TWO: The Use of Insecticide-Treated Nets (ITNs) In the Control of Malaria 3
2.1 Long-Lasting Insecticidal Nets 5
2.2 Benefits of Insecticide Treated Nets In Malaria Control 7
2.3 Challenges in The Use of Insecticide Treated Nets In Malaria Control 8
CHAPTER THREE : The Use Of Indoor Residual Spraying In The Control Of Malaria
3.1 Benefits of Indoor Residual Spraying In Malaria Control 11
3.2 Challenges in the Use of Indoor Residual Spraying In Malaria Control 12
CHAPTER FOUR: Combining ITNs and IRS for Malaria Control
4.1 How Widespread Is Combined Use Of ITNs And IRS In Africa? 14
4.2 The Potential Benefits of Combining ITNs With IRS? 14
4.3 Significance of IRS And ITNs in the Current Malaria Control Strategy 19
Malaria is a mosquito-borne infectious disease that affects humans and other animals (WHO,2014). Malaria continues to be a major global health problem despite more than 100 years of research. It is a complex disease caused by four plasmodial species Plasmodium falciparum, Plasmodium ovale, Plasmodium vivax, Plasmodium malariae (Oaks et al., 2010) and recently, one more species Plasmodium knowlesi (Bronneret al., 2009).Malaria is transmitted by the bite of an infected female Anopheles mosquito. Transfusion of blood from infected persons and use of contaminated needles and syringes are other potential modes of transmission. Congenital transmission of malaria may also occur.
Mature forms of plasmodium falciparum (asexual stage and gametocytes) can adhere to the vascular endothelium of several organs (lung, heart, brain, liver and kidney) (scherf et al., 2008). Liver is involved in malaria at two stages; during the pre-erythrocytic cycle and the erythrocytic phase (Anand et al., 2005). Histopathological findings reported in literature are: congestion of hepatocytes, swollen hepatocytes, paralyzed RBC, cholestasis and steatosis (kochar et al., 2003). Placenta malaria has been associated with elevated risk of miscarriage, fetal anemia , congenital malaria, perinatal mortality and low birth weight (Bardaji et al., 2011). The signs and symptoms of malaria typically begin 8 – 25 days following infection (fairhurst et al., 2010). But may occur later in those who have taken antimalarial medications as prevention (Nadjm et al., 2012). Malaria causes symptoms that typically include fever tireless, vomiting, chills and headache (caraballo et al., 2014). In severe cases it can cause yellow skin, seizure, coma, or death. Maralia has several serious complications. Among these is the development of respiratory distress, which occurs in up to 25% of adults and 40% of children with severe plasmodium falciparum malaria (Taylor et al., 2012). Coninfection of HIV with malaria increases mortality (Korenromp et al., 2005). Complications may include enlarged spleen, enlarged liver, severe headache, low blood sugar and hemoglobin in the urn with renal failure (Bartoloni et al., 2012). Malaria in pregnant woman is an important cause of stillbirths, infant mortality, abortion and low birth weight (Hartmem et al., 2010). Particularly in plasmodium falciparum infection (Rijken et al., 2012).
WHO estimates that in 2015 there were 214 million new cases of malaria resulting in 438,000 deaths. Malaria is presently endemic in a broad band around the equator, in areas of the Americas, many parts of Asia and much of Africa, in Sub–Saharan Africa, 85-90% of malaria fatalities occur.
Malaria adversely affects man in a variety of ways, it debilitates his physical health. It reduces the ability of man to wirk thus affecting productivity, whether in the public or private enterprise. It causes death especially of children under the age five years and pregnant women. (Aribodor et al., 2012). Malaria consumes up to 40% of public health expenditure in high transmission areas, Africa alone suffers US$ 12 billion in lost GDP every year (Kitua et al., 2011).
Few vector control methods can be considered as effective against malaria mosquitoes as insecticide-treated nets (ITNs) and house spraying with residual insecticides (IRS). In recent years, endemic countries using the two methods singly or in combination have reported significant declines in malaria related morbidity and mortality (Kleinschmidtet al., 2009). A review of previous intervention trials has suggested that ITNs can reduce malaria cases by 39% to 62% and child mortality by 14% to 29% (Okumu and Moore, 2011). Similarly IRS has been shown to significantly disrupt malaria transmission, eliminate malaria vectors and reduce malaria incidence (Mabasoet al., 2004).
Today, universal coverage with long lasting insecticide-treated nets (LLINs) or IRS is actively promoted as the main prevention strategy under the WHO endorsed malaria control and elimination plan (WHO, 2009). Where both ITNs and IRS are considered, the two methods are mostly used concurrently, within the same households, even though some national strategies do emphasize one method more than the other (WHO, 2010). Indeed, previous and current WHO guidelines have recommended the combination of ITNs and IRS in various malaria transmission scenarios, more so for holoendemic and epidemic situations (WHO, 2009). Other than intermittent preventine treatment (IPT), artemisinin-based combination therapy (ACT) and improved case detection by rapid malaria diagnostic tests (RDTs), recent declines of malaria are mostly attributable to expanded use of ITNs and IRS (Fegan et al., 2007).
In this paper, recent trends of using ITNs and IRS are explored with special emphasis on:
1) Significance of the two methods in current malaria control agenda,
2) Potential benefits of combining the methods.
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