PREVALENCE OF SCHISTOSOMA HAEMATOBIUM AMONGST CHILDREN OF SCHOOL AGE AND
ASSOCIATED URINARY ABNORMALITIES IN
EBONYI NORTH
CHAPTER ONE
INTRODUCTION
Schistosoma
haematobium is the causative agent of
urinary Schistosomiasis also called Bilharziasis named after a young German
parasitologist Theodor Bilharz, who first identified the parasite during
autopsy in Egypt .(Roberts; 2010).
It is an
important digenetic trematode and is
found in Middle East , India , Portugal
and Africa. It afflicts the poor , rural villagers , especially school aged
children , women and fishermen who lack access to safe water and sanitation ,
and where daily activities bring them into direct contact with infected water
sources.
The adult organism are found in the venous plexuses
around the urinary bladder and their released eggs traverse the wall of the
bladder causing haematuria and fibrosis of the
bladder. The bladder become calcified and there is increased pressure on Ureters and kidneys otherwise known as
hydronephrosis . Inflammation of the
genital due to S. haematobuim may contribute to the propagation of HIV
(Leutscher et al ;2005).
Studies have shown the relationship between S haematobuim and the development of squamous cell carcinoma of the bladder (Khurana et
al;2005).Schistosomiasis or Bilharziasis is generally applied to blood fluke
infections caused by different species of blood
flukes namely Schistosoma haematobuim , S. mansoni ,S.
japonicum, S .intercalatum ,and S
.mekongi.(Nnochiri;1975).
Schistosomiasis
is one of the major communicable disease of public health and socio-economic
importance of the tropical and sub- tropical
region. The disease has been
reported to be the second to malaria as
a source of human morbidity ( Ukoli; 1992). It is one of the major occupational
hazards in rural areas of developing
countries. It is second to none in prevalence among water borne parasitic
diseases(WHO;1985) and (Doumenge et al;1987).
Schistosomiasis or Bilharziasis is not only endemic in Nigeria but is also known to be prevalent in all
countries of Africa (Wurapu et al ;1989). According to estimates of WHO,(1984),
at least 200 – 300 million are infected with the disease (and another 600
million are at risk of infection) and endemic in 74 developing countries.
Estimates suggest that 85% of all schistosomiasis cases are now in sub –Saharan
Africa. ( Chitsulo l et al;2000).
WHO, (2012) estimates that at least 243 million people required treatment for
schistosomiasis in 2011 and the number
of people treated in 2011 was 28.1 million. Nigeria as one of the countries
known to be highly endemic for urinary
schistosomiasis with estimated 101.28 million persons at risk and 25.83 million
infected (Uneke et al; 2007). The estimates
for morbidity and mortality in affected populations are high with school age
children.
Two forms of Schistosomiasis are recognized in humans
.They are urinary schistosmiasis caused by S
. haematobium .It is also known as the vesical type of the disease characterized by passage
of blood stained urine ( haematuria ).The other form is called intestinal
schistosomiasis which is caused by S.
mansoni, S .japonicum and S .intercalatum .
Some
urinary abnormalities are associated
with S
haematobium infection, The presence
of blood in urine known as haematuria
and protein in urine known as proteinuria has been recorded in several
studies on S . haematobium infection.
Persons
affected by S. haematobium may develop cough , fever, skin inflammation
and tenderness of the liver because the spined eggs attach to vital organs and
cause tissue degeneration. Later stages
of the disease may be characterized by the swelling and damaging of the bladder
, liver and other organs .The eggs of S. haematobium can clog the bladder
neck and cause infection .Many
researchers have also observed damage on other body structures . Chronic
Schistosomiasis raises the incidence of
bladder cancer in many middle Eastern countries( Roberts et al;2000).
Calcified
eggs embedded in the bladder wall increase the chances of blockage of the
vessels .Although other species of Schitosoma
also cause Medical problems ,Schistosoma
haematobium is the only species that
affects the Human urinary system ( Basch; 1991).
Urinary
Schistosmiasis is often chronic and can cause pain, secondary infection, kidney
damage as well as cancer. Painful or difficult urination (dysuria), Blood in
urine ( haematuria), urethral obstruction, kidney damage from obstruction of
urine ( obstructive nephropathy) ,no urination ( anuria) are all accompanied
signs and symptoms. The parasite also causes chronic urinary tract bacterial
infection .The bladder may also develop tubercles, polyps, ulcers, sandy
patches, cystitis cystic, and or leukoplakia that are visible upon endoscopic
examination.
Late
complication after years of infection includes squamous cell carcinoma
Incidence of
urinary schistosomiasis in Nigeria and
surveys reporting the prevalence in some towns and communities has been
documented viz: Cowpear;(1973), Ozumba et al;(1989), Adewumi et al;(1990),
Emejulu et al ;(1994), Akogun;(1996), Edungbola et al;(1998),Daniel et al;(2001),
Adeyeba et al;(2002), Nnoruka;(2000),
Idris et al (2002), Ekejindu et al;(2002), Okon et al;(2002),Alozie et al
(2004), Onwe ;(2005),Uneke et al;(2007), Uwaezuoke et al;(2007) Obiukwu et al
;(2008),Adeoye et al;(2008),Nmorsi et al;(2007), Mbata et al (2009), Odikamnoro
et al ( ), Okwelogu et al (2012).
But out of
these studies non has incorporated the associated urinary abnormalities in the research work.
AIMS AND
OBJECTIVES
Work has not been done on the prevalence of
S. haematobium amongst
children of school age and associated urinary abnormalities in Ebonyi North. Hence this work therefore is aimed at
1. Determining the prevalence of urinary schistosomiasis and
associated urinary abnormalities amongst children of school age in Ebonyi
North.
2. Determining the socio- economic and environmental factors
that can lead to urinary schistosomiasis amongst the children of school age and
the communities at large .
3. Developing (based on the outcome of the study) strategies to
control/eradicate the disease in the community.
CHAPTER TWO
LITERATURE
REVIEW
Records indicates that Bloody urine was a well
recognized disease symptom in Northern Africa in ancient times. About 1950 BC Egyptian Pharoahs wrote of urinary
bladder disturbances that probably were Schistosoma haematobium .
The hieroglyph used to denote the disease was a
dripping penis.Atleast 50 reference to this condition have been found in
surviving Egyptian papyri and calcified eggs of S. haematobium have been found in Egyptian mummies dating from
about 1200BC. ( Roberts et al ;2010).
The first Europeans to record contact with S.haematobium were surgeons with
Napoleon’s army in Egypt(1799-1801). They reported that hematuria was prevalent
among the troops, although the was unknown. Over 50 years later precisely 1851
a young German pathologist Theodor Bilharz discovered the parasite that caused
it while working at Kasr El-Eini Hospital in Cairo. It was discovered some
years later that 30% to 40% of the population in Egypt bore infection of S. haematobium .
In 1858 Weinland proposed the name schistosoma but it
was named Bilharzia by Cobbold after its discoverer Theodor Bilharz. This later
name became widely accepted throughout the world. However, the strict rules of
zoological nomenclature decree prefers Schistosoma and is thus the current name of the
parasite today. Schistosoma is an apt name,
referring to the “split body” (gynecophoral canal)of the male.
While information was accumulating on biology of S. haematobium some people began to
doubt whether it was a single species or whether two or more species were being confused. This problem was more
confounded by the observation in some
patients of eggs with lateral
spines and others with terminal spine in both urine and feces.
In 1905 Sir Patrick manson decided that intestinal and vesicular(urinary bladder)
schistosomiasis were distinct disease caused by distinct species of worms. He
derived his conclusion after examining a man from West Indies who had never
been to Africa and who passed laterally spined eggs in his urine (Robert et al
;2010).
Sambou in 1907 name the parasite producing laterally
spined eggs Schistosoma mansoni
.
In 1915 Leiper an English Scientist discovered the
intermediate snail host. By working in
Egypt, he discovered that cercariae emerging from the snail Bulinus spp could infect the vesicular
veins of various mammals and they always produce eggs with terminal spines.
Also those emerging from a different snail,Biomphalaria
spp ,infected intestinal veins and produced laterally spined eggs.
GEOGRAPHICAL
DISTRIBUTION
Schistosomiasis is estimated to occur world- wide ,
infecting 200million people and endemic
in 74 developing countries while leaving over 600 million people at risk
(Chitsulo et al;2000).
The infection is most prevalent in Africa , Middle
East ,South America, Caribbean, Southern
China and South east Asia (WHO;1985).Estimates suggest that 85% of all
Schistosomiasis is endemic in 54 African countries and the Eastern
Mediterranean. It is found in much
tropical and sub-tropical Africa and also occur in Iran ,Saudi Arabia, Syria,
Arab republic, Yemen in Maharashtra state in India and in several Indian ocean
islands including Mauritius, Pembina, Zanzibar and some smaller island off the
East African coast(Cheesbrough;2003).
S. mansoni,the causative agent of
intestinal schistosomiasis is prevalent in 52 countries. It is wide spread in
many African countries, Madagascar, and parts of Middle East, South America(
especially Brazil), and the west Indies. S
.mansoni occurs with S. haematobium
in 41 Countries of Africa and the Eastern Mediterranean .( Cheesbrough;2003).
S. japonicum is widely distributed in mainland China, parts of the
Philipines and Western Indonesia .
S. mekongi is found in Lao people’s Democratic Republic,
Cambodia, and Thailand in the Mekong River Basin ( Cheesbrough;2003).
S
.intercalatum is limited in its
distribution mainly to West and Central Africa , that is Zaire, Gabon and
Cameroon .Republic of Sao Tome (island off West Africa) recently recorded
infection of S. intercalatum.
Cheesbrough,(2003) noted that the development of
irrigation channel and Dams, for
hydroelectric power and flood control have altered the distribution of
Schistosomiasis in several countries,example Aswan lower dam in the United Arab
Republic(Egypt), Akosombo Dam in Ghana,the Senna Dam in Sudan, Kainji Dam in
Nigeria ,and the Kariba Dam in Zimbabwe. Water development projects for water
conservation equally contributed.
In Nigeria, pocket
of foci of infection have been documented in various parts of the country. In
the Northern region, S .haematobium
is marked particularly by heavy infection rates. These include the territory
extending from Katsina, Kano, Zaria and Kaduna to the Western frontier, in the
region of Birinin Kebbi ,Argungu, Kankiya area.( Nmorsi et al;2005). In these
area Schistosomiasis associated with haematuria infection rate of up to 60%-95%
have been recorded.(onwe;2005).
Other Northern region include Wulgo region of lake
Chad basin, the riverine area along the Niger from Wawa to Pategi and Bida,
Niger( Cowper;1963).
In the western
region, S. haematobium is universally
distributed. The highest infection rates are found in Ibadan, Oyo, Abeokuta and
Epe area. Cowper, (1963) has also reported the endemic foci in Ogoja province
and around Owerri of the Eastern region .Akinkugbe,(1962) states that urinary
infection due to S. haematobium is
endemic all over Nigeria ,but later work by
Cowper,(1963) has narrowed the endemicity in Nigeria down to Western and
Northern regions. However several works by Ekejindu et al;2002, Uneke et
al;2007, Uwaezuoke et al;2008, Mbata et al ;2009. All indicate prevalence in the Southern parts of Nigeria.
MORPHOLOGY
Schistosoma spp. are generally similar
structurally with slight differences as listed in Table 1
Comparative
Morphology of the three primary species of Human Schistosomes
Characteristics S.
haematobium S. mansoni S .japonicum
Tegumental papillae:
Small tubercles Large
papillae Smooth
Size:
Male
Length 10-15mm
10-15 mm 12-20 mm
Width 0.8-1.0 mm
0.8-1.0 mm 0.5-0.55mm
Female
Length ca.20mm
ca.20mm ca.26mm
Width ca.25mm
ca.25mm ca.0.3mm
Number of testes: 4-5 6-9 7
Position of ovary: Near midbody In anterior half Posterior to midbody
Uterus : With
20-100eggs at one time Short; few eggs
at one time Long; contain 300 Eggs.
Vitellaria: Few follicles, posterior to ovary Few follicles, posterior to ovary In lateral view, Posterior quarter Of body Egg: Elliptical, with sharp terminal spine Elliptical, with sharp lateral spine Oval to almost spherical:
112-170
m by 40-70
m 4-175
m by 45-70
m 70-100
m by 50-70
m
TABLE by: (Roberts et al; 2010)
They are not flat, leaf like worms like
other Trematodes. They have narrow elongated bodies and have separate sexes (
Ochei et al;2000).Considerable sexual dimorphism exists in the genus, males
being shorter and stouter than females.
The male worm (Fig 1) is colorless,
cylindrical and measures 10mm-20mm. The males have a ventral, longitudinal
groove ,the gynecophoral canal, where the female normally resides.
The mouth is surrounded by a strong oral
sucker, and the acetabulum is near the anterior end.There is no pharynx .The paired intestinal ceca
converge and fuse at about the midpoint of the worm and then continue as a
single gut to the posterior end.
Males possess 5-9 testes according to
species, each of which has a delicate
Vas deferens. The later dilates to become a seminal vesicle, which opens
ventrally through the genital pore immediately behind the ventral sucker. The
integument is finely tuberculated.
The female worm (Fig.2) is cylindrical,
threadlike, often reddish black in color and longer than the male, measures
20mm in length and 0.35mm width and has pointed extremities.( Roberts
et al;2010). The sucker of the females are smaller and not so muscular as those
of the males and tegumental tubercles if
any are confined to the ends of females.The ovary is anterior or
posterior to or at the middle of the
body, and the uterus is correspondly short or long depending on species.
The eggs (Fig.3) are compact, elongated
spindles, dilated in the middle and they measure about 112-170um in length by
40-70um breath.
TRANSMISSION AND LIFE CYCLE
This occurs in Fresh water when intermediate snail host
release infective form (cercaria) of the parasite into wter. People become
infected by direct physical contact with water containing infective cercaria(
while swimming, washingcloth ,bathing in water and during agricultural work). Bulinus snails are mainly the
intermediate hosts for S. haematobium
while Biomphalaria is for S. mansoni and amphibious Oncomelania snails is for S. japonicum.
When released
from the snail host, the infective cercariae swim, penetrate the skin of the
human host, and at the same time shed their forked tails (bifurcated) becoming
Schistosomulae. The schistosomule
Migrate through the tissue and finally enters a blood
vessel. Through the blood it is carried to the heart, the lung and then to the
liver. The worm begin to grow and mature into an adult within the liver
sinusoids. Eventually they migrate against the portal blood flow into the
mesenteric, vesical or pelvic venules.
The delicate adult worms reside in the venules in
pairs ,the female lying in the gynecophoric canal of male. Depending on the
species, eggs are passed daily into the venules (e.g about 200 by S. haematobium, 300 by S. mansoni and 3500 by S. japonicum). Egg deposition occurs in
the venules of the bladder ( for S.
haematobium ) or small venules of the intestine and the rectum( for S.mansoni and urethra or into the
intestine and are ultimately released from the body in the urine or feaces .
The eggs are immature when first laid and contain a mature miracidium by the
time they are released in the urine and feces.
When the egg comes in contact with water the mature
miracidium is liberated. It swims actively in the water till it finds a suitable snail host which
varies from species to species. The Miracidium penetrates the snail
intermediate host and develops through the stages of a mother sporocyst which produces daughter sporocyst that
finally develop into cercariae with a forked tail .These cercarae are released
by snail into water to infect man through skin penetration ( Ochei et al;2000).
EPIDEMIOLOGY
Urinary Schistosomiasis caused by S.
haematobium is reportedly endemic in 53 Countries in the Middle East and most of the African
countries ( Chitsulo et al;2000). Nigeria is one of the countries known to be
highly endemic for urinary schistosomiasis with estimated 101.28 million
persons at risk and 25.83million people
infected (Uneke et al ;2007).
Human waste in water containing intermediate hosts is
the single most important epidemiological factor in schistosomiasis and
availability of suitable snail species (Roberts et al;2010).Survival of these
parasites depends on human habits of polluting water with their own feces.
Human are apparently the only important host in most
area of high endemicity,( Markel et al;1996).In Africa non human primates
insectivores and wild rodents are found to harbor the schistosmes where as in
Brazil several species of marsupials and rodents carry the infection. The
importance of these reservoir hosts in maintaining and spreading the disease to
human probably varies from one area to the next.
Extension of the disease into new areas still occurs
with the migration of infected people and the Agricultural Development of
virgin land where the snail host is present. Irrigation and the establishment
of artificial bodies of water combined with unsanitary practices may quickly
result in new foci of high endemicity. Since the snail intermediate host is
entirely aquatic, the aqueous
environment (water flow, vegetation, water temperature, and PH ) determines
snail density and distribution.( Markel et al ;1996).
As far as it
is known, human remains the most important
host for S. haematobium. The
snail intermediate host apparently has less stringent requirement for water
temperature than snail host of S.
mansoni. This may partly explain the relatively wide distribution of S. haematobium on the African continent (Markel et al;1996).
In some areas
of high endemicity in East Africa ,the snail lives in relatively small bodies
of water that may dry up during part of the year. The snail the estivate while buried in the mud but retain the
infection and resume shedding of
cercariae when the rain season begins.
Other factors relating to snail intermediate host
include presence of right species for transmission, the reproductive capacity
of these snails, the number of
cercariae shed at a given time and
seasonal variation in snail infection
rate ( Anosike et al ;2003).
Immigration and
population movement has introduced the infection to new areas and many people
from non endemic areas have moved to areas where transmission occurs. Other
factors that influence the amount of Schistosoma
haematobium infe ction in an area include those related to human
behavior, local custom , tradition, religion and the pattern of water used for
economic and recreational activities such as swimming, fishing, irrigation, and
washing( Onwe;2005).
Clearly, economic and education level of population
will influence transmission of the disease, and age and sex are important
factors as well. Males usually show the highest rates of infection and the most intense
infections.The most hazardous age is the second decade of life( Roberts et
al;2010).
Nmorsi et al, (2007) in a study assessing the ova of Schistosoma haematobium in
the urine of 138 volunteers Ihieve ogben Edo state Nigeria revealed 43
positive result (31.2%) with children
having higher prevalence of urinary Schistosomiasis 30 (41.1%) than their adult
counter parts. This was attributed to high exposure factor among the children
as had been previously reported by Nmorsi et al,(2005) and Egwunyenga et al
,(1994).
Also in a study of the prevalence of urinary
Schistosomiasis in ogbadibo Local Government Area of Benue state Nigeria , out
of 657 urine samples examined ,300(46.6%) showed the presence of S haematobium .Of the 300 positive samples 152(23.13%) were from
males and 148(22.52%) were from females. In addition Uneke et al,(2007) in a
survey of S. haematobium conducted
among school children in Ohaukwu and Onicha local Government area of Ebonyi
state Nigeria indicates that out of a total of 876 pupil examined 235(26.8%)
were infected with S .haematobium a
total of 129(27.01%) were males while 106(26.6%) were females of those infected
supporting the fact that males are more infected than the female counter part .
This was equally supported by the study conducted by Okwelogu et al, (2012)
.This may be attributed to high exposure of the males who are mostly involved
in recreational activities of Swimming and Agricultural endeavours.
In a study of
the prevalence and intensity of infection with S. haematobium amongst primary school children of Taga Tanzania in
East Africa ,the analysis of S.
haematobium infection in four urban and four rural primary schools in the
area . Out of the 2270 children examined 38.4% were infected.
In urban school 23.1% of 1411 children were infected
compared to 63.6% of 859 children in rural school. Prevalence was higher in
rural school children than urban school children. This probably is due to the level of
exposure of urban and rural children.
The urban children were not very much exposed to fetching water from streams
like the rural children except in situation where the tap water is not
available (Bailey et al;1970).
According to Anosike et al,(2003) in the investigation
on the prevalence and severity of infection with S. haematobium amongst inhabitants of Ebonyi/Benue river Valley,
South eastern Nigeria between August 2000
and June 2001 showed that of 3296 subjects examined 776(23.5%) were
excreting the eggs of S. haematobium in
their urine . The prevalence and severity of infection increased with age from
6 to 25 years. This was attributed to the presence of infected snail host in
the stagnant ponds of which many snail species were recorded including Bulinus globosus and Bulinus
truncates.
Cowper,(1963) stated that infection is rare in infants
below 4 to 5 years. The highest egg output occurs between 12 and 20 years. The
infection rate is generally highest among children of 6 to 8 years by
(Malataway et al; 1984) , 10 to 14years by (Bruce;1990). The reason according
to Malataway et al is that at 6 to 8years the only hobby of children is
swimming and that at age of 9-11 years they start other activities like reading,
footballing and TV watching. This
confirms with the work of Cowper,(1963) who in school surveys in the western
region in Nigeria recorded an infection
rate of up to 20% in children under 14years.
SYMPTOMS AND PATHOGENICITY
Following penetration of the skin by cercariae of Schistosome that infects humans a
transient reaction may be seen .Petechial hemorrhages occur at the site of
penetration with some localized edema and pruritus which reach a maximum in 24
to 36 hours and disappear in 4 days or less.(Markell et al; 1996). During the
succeeding 3 weeks there may be transient toxic and allergic manifestations. These
may be very mild and may pass unnoticed or there may be generalized malaise,
fever, giant urticaria, vague intestinal complaints and so forth, partly
depending on the intensity of infection.
Migration of the worms throughout the lungs may cause
cough or hemoptysis, soon the developing Schistosome
reach the liver , acute hepatitis may develop. When the fluke reach the
mesenteric or vesical venules and egg laying commences ,the acute stage of the
disease is seen. The unset of this stage may occur 1 to 3 months after
infection (Markell et al;1996).
Symptom of the acute stage may range from mild to
severe, and the degree of reaction is not necessarily proportional to the
number of parasites involved. Clinical disease at this stage is usually seen
only in relatively heavy infection or in persons recently arrived in an endemic
area. With the extrusion of eggs through the wall of the intestine or bladder ,
there may once again be generalized malaise, fever, urticaria, abdominal pain,
and liver tenderness.
In S. haematobium infections , there is
often hematuria at the end of micturition. While in S .mansoni or S. japonicum
infections there may be diarrhea or dysentery at this stage . The eggs are
responsible for much of the pathology associated with the disease. Some of the
eggs are trapped in body tissues. Immune reactions to eggs logged in tissues
are the cause of the disease (Ogbeide et al;2004).
As soon as the eggs are produced, initially they are
trapped in the fine venules. The eggs liberate a number of enzymes which
facilitates their passage to the lumen of the bladder or intestine. In S. haematobium infections, the spine on
the egg may cause haematuria (Ochei et
al;2000). Urination become painful and is accompanied by progressive damage to
the bladder, ureters and then the kidneys. Bladder cancer is common in advanced
cases (WHO;1985).
IMMUNOLOGICAL
RESPONSE:As the eggs are deposited in tissues their antigens invoke an immune response in
the host leading to the formation of granulomas around the eggs in tissues. The
wall of the intestine or bladder become inflamed and thickened causing
mechanical obstruction. Some eggs are swept into blood circulation and
deposited in the liver and other organs in the body .Cerebral symptoms are
commonly seen in S. japonicum
infection while pulmonary involvement is more common with S. haematobium infections.(Ochei et al;2000)
URINARY
ABNORMALITIES: Urinary
abnormalities are often associated with S.
haematobium infections. Light infections are usually asymptomatic. Dysuria,
urinary frequency and haematuria are early symptoms and signs, but in endemic
areas they are so frequent as to be in
large measure. Nmorsi et al, (2005) found a close association between
eosinophiluria, proteinuria, haematuria specific gravity and turbidity in the
urine with the presence of S. haematobium
ova in urine. Ramsay, (1952) in his survey of Schistosomiasis in Northern Nigeria
found that in sokoto area practically everybody suffers from gross hematuria at
some point in early life. Terminal hematuria is usually the first sign of
infection. Eosinophiluria is a constant finding in urinary Schistosomiasis.
Chronic bacteriauria is common with
numerous pus cells in urine. Obstructive uropathy occurs primarily in persons
with high total egg burden. Bladder cancer usually a squamous cell carcinoma,is seen much more
frequently in patients with heavy S.
haematobium infections than in the general population. (Markell et
al;1996). The cancer occurs primarily in areas of the bladder where there has
been heavy egg deposition. It is thought that these heavy egg concentrations
promote urothelial carcinogenesis. A nephrotic syndrome is occasionally seen in
both S. mansoni and S. haematobium infections.
LABORATORY
DIAGNOSIS
Microscopic identification of eggs in urine or stool
remains the most practical method for diagnosis of Schistosomiasis . According
to Ochei et al, (2000) there are two methods in use for the detection of Schistosoma eggs in urine.
1. The sedimendation/centrifugation technique which is less
sensitive but cheaper and simpler to perform.
1.
The filtration
technique which is used when quantitative information is required.
2.
Detecting eggs in
a rectal biopsy or bladder mucosal biopsy is also another method of diagnosis
when urine examination is negative or unreliable due to egg encapsulation in
the tissues (Cheesbrough;2003). The biopsy tissue can be crushed between two
slides and examined microscopically to identify the species. If the preparation
is too thick, add a drop of 4% KOH to clear the tissue. Digest the tissue in 4%
KOH at 370c for 6 to 18hours. Centrifuge and examine the sediment
for ova.
3.
Serodiagnosis is
not very useful because of cross reactions with other helminthes, slow
immunological response of the host and persistent elevated titres even after
successful treatment (Ocheiet al;2000) and (Roberts et al;2010). Though a
diagnostic technique taking advantage of the polymerase chain reaction (PCR) to
detect a parasite DNA may offer a significant improvement.
Other techniques like intradermal test , flocculation
test can be adopted for field use. However these methods are used only as
complement to the urine microscopic examination method.
URINE EXAMINATION BY
SEDIMENTATION/CENTRIFUGATION TECHNIQUE:
Finding the eggs or occasionally the miracidia of S. haematobium in urine . A quantitative
report can be required and determined by
the number of eggs/10ml of urine.
The excretion of S.
haematobium eggs in urine is highest between eggs in urine is highest
between 10.00 h and 14.ooh with a peak around midday (Cheesbrough;1998 ).
Cheesbrough, (1998) noted that a heavily infected persons may sometime present
no eggs in urine sample due to the irregular pattern of egg excretion. Also
neither excercising before passing urine nor collecting terminal urine (that is
the last few drops of urine) increase
the number of eggs present in the
specimen as was once thought (Cheesbrough;1998). And to avoid miracidia
hatching from the eggs, precaution should be taken by keeping the specimen in
the dark.
PROCEDURE
1. Collect 10ml of urine in a clean dry container.
2. Report the appearance of the urine
3. Transfer 10ml of well mixed urine to a conical or
centrifuge tube and centrifuge at 500-1000g to sediment the Schistosme eggs ( avoiding at
centrifuging at a greater force because the eggs may hatch. In the absence of a
centrifuge the urine can be allowed to stand and the eggs to sediment by
Gravity for 1hour.
4. Discard the supernatant fluid .Transfer all the
sediment to a slide , cover with a cover glass and examine the entire sediment
microscopically using the 10x objective with the condenser iris
closed sufficiently to give good contrast.
5. Count the number of eggs in the preparation and
report the number per 10ml of urine . If more than 50eggs are present there is
need to continue counting. Such count indicates heavy infection
(Cheesbrough;1998)
FILTRATION
TECHNIQUE.
Filtration is the most sensitive rapid and
reproducible technique for detecting and quantifying S
.haematobium eggs in urine. However, the polycarbonate membrane filters used in
filtration technique are expensive .Other types of filters like Nytrel woven
filters can equally be used.
MATERIALS
REQUIRED : includes:
--10ml syringe.
--Syringe filter holder ( swinnex type) 13 diameter.
--Polycarbonate membrane filter of 13mm diameter and
12-14um pore size. This can be disinfected
with bleach and be reused several times.
PROCEDURE:
1. Using blunt-ended forceps , carefully place a polycarbonate
filter on the filter support of the filter holder. Re-assemble the filter
holder and attach it to the end of 10ml Luer syringe.
2. Remove the plunger from the syringe and fill the syringe to
the 10ml mark with a well mixed urine .Replace the plunger. Holding the syringe
over a beaker or other suitable container, slowly pass the urine through the
filter.
3. Remove the filter holder and unsecrew it. Using blunt ended
forceps, carefully remove the filter and transfer it face upwards to a slide.
Add a drop of physiological saline and cover with a cover glass.
4. Using the 10x objective with the condenser iris
closed sufficiently to give good contrast , examine systematically the entire
filter for S. haematobium eggs and
report the number per 10ml urine .(
Cheesbrough;1998).
N:B
Differentiating non-viable from viable Schistosome eggs on a filter can be done by staining a preparation with 1% trypan blue in
physiological saline. A drop of stain is added and the preparation is left for
30minutes at room temperature.
Non-viable eggs will stain blue while the viable eggs
will remain unstained.
PREVENTION AND CONTROL
According to Roberts et al, (2010), the control of
Schistosomiasis as with many infectious diseases involves a multifold approach
which includes;
1. Education or public health awareness of the populace to
prevent transmission.
2. Massive chemotherapy or curing of infected persons.
3. Control
of vectors/intermediate host propagation.
3. Protective
vaccination.
Okwelogu et al,(2012) agrees with these measures while
Uneke et al ,(2007) implored the integration of methodologies and managerial
tools to improve preventive strategies with emphasis on health education,
information and communication.
Education of the population though potentially very
effective is often exceedingly difficult due to low level of literacy, poverty,
customs and traditional belief of the people involved. However, Education is
the prerequisite for all control measures, since without understanding of the
life cycle of the parasite attempts at its eradication are doomed to failure.
With education programs brought to the people, it has been demonstrated in
areas such as China that progress can be made in parasite eradication ( Markell
et al;1996).
Differences in the snail hosts of the various Schistosome spp.in some cases dictate
different control measures. Mollusciciding and
biological control through the use of snail eating fish or birds or even
competing species of snails as has been done with some success in Puerto Rico
and Brazil (Giboda et al;1997), environmental modification or various
combinations of these measures.
Proper disposal of urine and feaces keeps eggs from
hatching to initiate the cycle . This may be difficult to enforce in places
where cultural and religious practices of people is tied to it. Also places
where human excrement is of great economic importance being used as fertilizer,
should be discouraged.
Other challenges of prevention is on teaching people
to avoid snail infested waters when their economic livelihood depends on
planting crops such as rice in these waters and where potentially snail
–infested waters is the only kind available for bathing, washing cloths and so
forth.
Niclosamide, a chloronitrosali-cylanilide , applied as
a 1% lotion to the skin before contact with snail infested waters seem to have
some value in preventing penetration of cercariae ( Abu-Elyazeed et al 1993).
Certain plants example (Balanites aegyptica ) were
cultivated for their molluscidal properties (Nigeria;1933).
In 1984, the WHO committee on the control of
Schistosomiasis, recommended a strategy for morbidity control with chemotherapy
as the major operational component (WHO; 1993). This was a departure from the previous strategy of
transmission control where the major aim was to eliminate the intermediate host
snails. In areas of high prevalence, chemotherapy especially through school
health programmes provides the most cost effective means for control.
Repeated chemotherapy ensures that levels of infection
are kept below those associated with morbidity (WHO/TDR; 2004). Key elements of
the control package consist of ensuring the availability of praziquantel in
primary health care services and the regular treatment of high risk groups
(school-age children and special occupation groups such as fishermen and
irrigation workers.
VACCINATION
The development of an effective vaccine would have
great potential value in the control of schistosomiasis and this area of
research is active ( Roberts et al; 2010).
Schistosomiasis has been controlled in many regions
such that it is no longer a major health problem in Japan, China, Iran, Mauritius,
Morocco, Saudi
Arabia etc. Thus with an adequate health
infrastructure resources and political will , the available tools for the
control of schistosomiasis can be used effectively (WHO;2004).
CHAPTER THREE
MATERIALS AND METHODS
STUDY AREA:
Ebonyi state was created out of Enugu and Abia
state in 1996. The state is located in
the south Eastern part of Nigeria. It is bound in the North by Benue state ,
East by Cross River state and West by
Enugu state.
The approximate population of the state is 2.093
million. There are thirteen local Government areas in the state which is
divided into three senatorial district – Ebonyi North, Ebonyi Central and
Ebonyi South. Ebonyi North is made up of four local Government areas—Abakaliki,
ohaukwu, Ebonyi and Izzi local Government Areas respectively . But the major
inhabitants are the two language spoken tribes of Ngbo and Izzi people. While the Izzi people
occupy three local Government area of Abakaliki, Izzi and Ebonyi, Ngbo people
only occupy Ohaukwu LGA.
The major economic activity of these people is farming
with very few people engaged in white collar jobs. The major sources of water
supply to the people is from Rivers, Dams, Streams, Stagnant ponds , few
shallow hand dug wells which are found in few rich families and
Bore holes provided by Government in some areas. These
ponds, stream, Dams and rivers harbor most
of the snail intermediate hosts from where the effective stage of the
parasite called cercariae emerge ready for transmission.
The people are equally massively engaged in
Agricultural farming like Rice farming which keeps them in constant contact to
water surfaces. The people are infected when they come in contact with water from
contaminated ponds and streams during farming, fetching water washing and swimming.
The mode of infection is by the penetration/piercing of the skin by the
cercariae .
MATERIAL AND
METHOD
A total of 500 pupils were sampled from seven primary
schools namely Central School Ngbo, Hill Top primary School Ngbo, Amaeffia
Community primary School Ngbo, Igbeagu Central School Izzi, Junction primary
School Nwezenyi, Oguzoronweya Primary School Ozibo and Okaria nkaleke community
primary school.
The age range of the children were between 6-18yrs and
their sex were also noted. The Teachers and pupils were enlightened on the
relevance of the study especially the public health significance. The method of urine collection was also explained
to them. After this the pupil were randomly
selected. The children were given serial number and containers were
distributed noting on the container their age and sex . Collection was done and
immediately taken to the laboratory for immediate examination
METHOD OF SAMPLE COLLECTION
Clean universal containers labeled ( Name, sex and
serial number) were distributed to the pupils randomly selected in each primary
School . The
pupils already enlightened were re-instructed on how to collect the urine
samples, particularly to include the last few drops passed (terminal urine)
.Collection of urine samples started normally between 11am and 1pm.
TRANSPORTATION OF COLLECTED SAMPLES
At the end of the collection exercise each day, the
urine samples were re-checked and carefully packed into the storage box for
immediate transportation to the laboratory for examination avoiding exposing
the sample to light that will induce hatching of the parasite.
LABORATORY METHODS OF ANALYSING THE URINE SAMPLES
1. Macroscopic Method: This involves noting the appearance of
the urine sample. The colour of the urine sample were noted ,some smoky brown,
bloody, turbid and cloudy appearance were noted.
Each urine sample were poured into clean
10ml centrifuge tube and properly labeled .
Chemical Examination of the urine was
carried out on each sample using commercially prepared test-strip (Example, Combi
9 urine test-strip ) noting the various parameters like Glucose, Protein,
Blood, Urobilinogen, Nitrite, Bilirubin and PH etc.
2. Microscopic
Method: This was done in line with Cheesbrough,(1998) recommendation for
Sedimentation Technique for Schistosoma
haematobium .Thus 10ml of urine were poured in to the centrifuge testtube.
The urine samples were centrifuged at 1000g for 5minutes.After centrifugation
the supernatant fluid was decanted and the sediment was mixed and a drop was
placed on a clean, grease free slide. It
was covered with a cover glass and examined using x10 objective and x40
objective of the microscope in search of the S haematobium ova.