**2.3 Six months – Five years**

## **2.3.1 Clinical features of complicated and uncomplicated malaria**

In the areas of stable malaria transmission, this group of children are the most affected in morbidity and mortality. Reporting the findings of severe malaria in Gabonese children, children Dzeing-Ella et al (2005) observed that most children with severe malaria are under 5 years old. Commonest features were anaemia, respiratory distress, cerebral malaria hypoglycaemia. Anaemia was commoner in children under 18 months of age, while cerebral malaria was commoner above 18 months. Poor prognostic factors were coma, hyperlactaemia and hypoglycaemia. Another study reporting uncomplicated malaria in febrile under 5 years children ( Ikeh & Teclaire, 2008) showed prevalences of about 52.2% and the most common presentation was fever. Most of the children within this age group at are various levels of developing immunity and yet have parasite rates that could range from 80-90%. This explains their potential to develop severe malaria.

#### **2.3.2 Use of clinical algorithms and predictors for malaria morbidity and mortality**

Development of clinical algorithms were initially done as guidelines to ensure that the young child at risk of potentially fatal diseases were identified and received prompt attention and commenced some management at the community level. In this guideline, the Integrated Management of Childhood Diseases [IMCI], children under 5 years of age, living in areas of high malaria endemicity were to be treated for malaria if they presented to a health facility with fever, temp >37. 5C. Studies by Tabitha et al (2005) found in a study that using a set of symptoms and signs with highest sensitivity and specificity and comparing these to parasitemia, a significant proportion of patients would have been sent home untreated. This tendency increased with increasing age. In situations as alluded to by the report of Khan et al (2005), the other issue was that often there were co-morbidities in febrile illness in some communities. Simply using algorithms for treatment of malaria might also lead to delay in treatment of other equally life threatening infections like Enteric fever which

Current Issues in Clinical and Laboratory Diagnosis in Malaria 167

diagnosis by clinical case definitions based on epidemiological factors may be a useful tool

However, Valerie et al (2010) again observed from studies done over 20years that there was a growing decline in malaria transmission in East Africa and a subsequent proportion of fever associated with Plasmodium falciparum. They concluded that the decline provides evidence for policy change from presumptive antimalarial therapy to laboratory diagnosis before treatment (Valerie et al 2009, 2010). Much has gone into training of personnel for laboratory diagnosis and as Ngasala et al (2008) reported on the impact of training in clinical and microscopy diagnosis of childhood malarial on prescription and health outcome: microscopy reduces prescription but there is great variation in accuracy of readings. With this observation, the caution by English et al (2009) might be only apt that rapid universal policy change that abandons presumptive antimalarial treatment for African children might

**3.2 Comparisons between rapid diagnostic tests and microscopy in malaria** 

Kain et al, 1998; Kilan et al, 2000; Omeara et al, 2005 as cited in Bell et al, 2006).

The gold standard for malaria parasite identification and quantification has been the microscopic examination of thick and fixed thin blood smears using Giemsa stain. In cases of anticipated low malaria parasite densities, care should be taken to maintain the pH of the stain around 7 and a freshly prepared stain achieves better results (Orogade et al, 2008). Other techniques utilised to enhance microscopy include the acridine orange fluorescent technique ( Keiser el al, 2002; Lowe et al, 1996; Nicholas, 1997). This has proved to be quite useful but requires the additional requirements of fluorescent microscopy. Maintenance of a good quality, effective microscopy service involves the provision of high quality supplies, reagents, microscopes as well as technical competence and an adequate work environment to prepare usable blood films (Coleman et al, 2002; Durrheim et al, 1997, Kachur et al, 1998;

Obstacles to lab diagnosis of malaria as have been reported in Mali (Dolo et al, 2010) are the same experience in most developing countries where malaria is endemic. These includeunderuse of laboratory diagnosis by clinicians, absence of qualified laboratory facilities in some locations, and poor continuous professional education of laboratory technicians.

Introduction of Rapid Diagnostic tests was intended to fill the need for accuracy, speed and reliability which standard microscopy has fallen short of. These are antigen detecting rapid diagnostic tests which detect the histidine rich protein 2(HRP2) and Plasmodium lactate dehydrogenase(pLDH) which are usually produced during the erythrocytic cycle. Several studies have evaluated the effectiveness of these tests compared with microscopy and the results have consistently shown high sensitivity and specificity but inability to differentiate mixed infections (Chinkhumba, 2010; Gatti et al, 2007; Tomas et al, 2001). However the successful implementation of RDT has been bedevilled by poor product performance, inadequate methods to determine the quality of products and a lack of emphasis and capacity to deal with these.(Bell et al 2006) Another group (Christopher et al, 2008) described the limitations of RDTs as having: all or none test results, inability to diagnose non falciparum malaria, variable heat stability and safety risks related to blood sampling (especially HIV and hepatitis B). Also of equal concern is that negative RDT results are often

in areas where laboratory facilities are not always available or reliable.

be premature and in fact cause more harm than good.

ignored and patients are treated anyway.

was commonly observed in their study. Algorithms on the one hand may lead to wastefulness of treatment supplies and on the other hand endanger lives for other possibly life threatening conditions.

### **2.4 School aged 5-12years**

### **2.4.1 Asymptomatic malaria parasitemia and its implication for malaria control**

The school aged child in an area of high endemicity typically has malaria parasite prevalence rates of up to 75%. Despite this high rates of parasitemia, theses children largely remain asymptomatic, having developed sufficient immunity which is both antiparastic and antitoxic to keep them from having clinical infection (Bruce Chwatt et al as cited by Orogade et al, 2002). In their study, Orogade et al (2002) also observed that these asymptomatic children had high levels of gametocytaemia (65%). Possible association between asymptomatic parasitemia and the utilization of vector control measures were analyzed. Vector control measure utilization was strongly related and inversely associated with the rates of ASMP. The estimation of ASMP is therefore recommended for use as an index for evaluation of malaria vector control programmes.
