The two methods in routine use are light microscopy and rapid diagnostic tests (RTDs) (Giribaldi et al., 2004; WHO, 2008).
a.
Light microscopic test: this is the direct microscopic visualization of
the parasite on the thick and thin blood smear of patients (WHO, 2010).
However, the risk of false negative microscopy is higher if the patient
has received a recent dose of an artemisinin derivative (Gobbi et al.,
2005). Microscopy can be used for speciation and quantification of
parasites and can be used to identify other causes of fever. A major
drawback of microscopy is that it requires well-trained, skilled staff
and usually an energy source to power the microscope (WHO, 2010).
b.
Rapid diagnostic test (RDTs): this type of test detects parasite
specific antibodys or enzymes and some have a certain ability to
differentiate species (Giribaldi et al., 2004). Some of the RDTs
developed are nucleic acid probes and immuno florescence for the
detection of Plasmodium within the erythrocytes; gel diffusion,
polymerase chain reaction etc (Giribaldi et al., 2004). Although RDTs
for detection of parasite antibody are generally more expensive, their
deployment may be considerably cost effective in many of the rural
settings (WHO, 2010). There have been progresses in diagnostic testing
and malaria treatment. The numbers of procured rapid diagnostic tests
(RDTs) and ACTs are increasing, as well as the reported rate of
diagnostic testing in the public sector in the African region, which
increased from 37% in 2010 to 61% in 2012 (WHO, 2013). As a result,
there has been a decrease in the number of suspected malaria cases
treated presumptively with antimalarial drugs (Gobbi et al., 2005).
However, millions of people with suspected malaria still do not receive a
diagnostic test, and many people with confirmed infections do not
receive appropriate treatment with a quality assured antimalarial (WHO,
2013).
2.1.7 Control of malaria
Control of malaria is undoubtedly
the best method of protecting a community against the disease. During
the 20th century, human efforts to control malaria and general
socio-economic development including access to health care have markedly
reduced the spread of malaria (Mishra et al., 2002). Control of this
deadly menace would therefore involve three living beings: man (the
host), Plasmodium (the agent) and Anopheles mosquito (the vector)
(Mishra et al., 2003). Several methods are used to prevent the spread of
malaria, to reduce transmission and manage morbidity among the infected
(Mishra et al., 2007). Such methods are broadly divided into
transmission control and morbidity control. These controls include:
A.
Chemotherapy: the treatment for various species is different
(Goldsmith, 2004), chloroquine and drugs like it will kill all four
species of falciparum when they are in the cell (Goldsmith, 2004),
prompt treatment is the best means for the management of all species of
malaria. This is because prompt treatment eliminates an essential
component of the cycle (the parasite) and thus interrupts the
transmission cycle (WHO, 2000). Chemotherapy of malaria is directed at
prophylaxis and presumptive treatment. The artemisinin-based combined
therapy (ACT) has in recent times been the most effective treatment for
malaria (Njuguna and Newton, 2004).
B. Biological control: This
method of control includes natural measures; natural limiting factors
are deliberately intensified without any reliance on chemical or
mechanical devices (WHO, 2008). Larvivorous fish are natural enemies of
mosquito larva and have been utilized with advantage for malaria control
e.g. Gambusia affinis, gold fish (Carasius quratus), Romanomermis
jingdeensis, a newly identified mamethid nematode has been found to
parasitize larva of A (Njuguna and Newton, 2004). It is capable of
recycling even in highly polluted water. Coelomyes, a fungus of the
Chytridomycete sub class is obligate parasite of mosquito and most are
specifically pathogenic, each to a single species complex of Anopheles
mosquito (Oliveira J., Daniel, 2001; Njuguna and Newton, 2004).
C.
Genetic control: This method reduces the reproductive potential of
insect by altering the hereditary material of the vector species
(Oliveira-Ferreira and Daniel-Ribeiro; Duffy, 2007). Genetic control may
be achieved by the following methods; (i). Irradiation – Males are
sterilized by ionizing irradiation- the principle is that the sterilized
males seek out and mate with the wild female in the natural populations
thus preventing the hatching of the eggs and lowering their
reproductive potential (Odhiambo et al., 2008). (ii). Another method of
genetic control is based on crossing sibling species of an insect. This
leads to hybrid that are released, their competition with fertile male
will eventually reduce the size of succeeding generation below the
normal threshold where transmission of malaria is possible (Duffy,
2007).
Arora and Arora (2005) outlined various measures in controlling malaria. These include:
i. Spraying residual insecticides such as DDT or marathion.
ii. Spraying the breeding sites with petroleum oils and paris green (copper acetoarsenite as larvicides.)
iii. Using larvivorous fish, Gambusia affinis
iv. Flooding and flushing of breeding places.
v. Eliminating breeding places such as lagoons and swamps
vi. Avoiding exposure to mosquito bites by;
a. Wearing long-sleeved clothing and trousers after sunset when the insects are most active
b. Using an electric matt to vaporize synthetic pyrethroid or burning mosquito coils.
c. Using bed nets impregnated with pyrethroid.
d. Application of mosquito repellents containing diethyltoluamide.
vii. Chemoprophylaxis
viii. Early diagnosis and prompt treatment of patients.
