CHAPTER ONE 1.0 INTRODUCTION 1.1 BACKGROUND OF THE STUDY Higher percentage of the people throughout the world serve as hosts to intestinal nematodes. Based on major and minor occurrences of these parasitic infection of intestinal nematodes, there have been notable implications of major public health problems which are most prominent in developing countries. The infection of intestinal nematodes is transmitted by eggs or larvae which the cycle of development begins within the human host when, depending on the species, they either actively penetrate the intact skin or are ingested or in very rare cases are inhaled. The larvae of the most widely prevalent species prevalent species of nematodes remain dormant but potentially infective for long periods in contaminated soil (optimum soil is warm, moist and shaded.); the larvae or cysts of other species are ingested when the flesh of reservoir host is eaten either raw or undercooked. In some instances, interruption of transmission (the key to effective long-term control) is dependent simply upon ensuring that meat and fish are adequately cooked. Interruption of transmission of soil-borne nematodes is currently not feasible in many endemic countries. 1 These said intestinal nematode infections affect one-fourth to one-third of the world’s population and of them all, the intestinal roundworm Ascaris lumbricoides is the most common. While the widespread majority of these cases are not showing any sign of Fig 1: Ascaris lumbricoides, adult female gross specimen infection, infected persons may declare pulmonary or potentially severe gastrointestinal complaints. Ascariasis, a resulting infection of Ascaris lumbricoides predominates in areas of poor sanitation and is associated with malnutrition, iron deficiency anemia, and impairments of growth and cognition. Ascaris lumbricoides eggs are found in the soil for which humans also act as reservoirs. The eggs are passed through the feces of the reservoirs but in other cases, can also be found on chopping boards, coins, door handles, fingernail dirt, fruits, vegetables, furniture, insects, nasal discharge, money and public bathrooms. 2 1.2 OBJECTIVES AND SIGNIGICANCE OF THE STUDY Seeing the mode of the statistical representation of major occurrences of the Ascaris lumbricoides parasite in the immediate environment of man, it is important to know the level of prevalence of ascariasis in the children of highly susceptible age groups within the locality. Mothers are seen to be mostly concerned about worms in their children than any other major health risk. This calls for a reason to know the approximate statistical evaluation of how often this parasite occurs in Igbesa, Ado-Odo/Ota Local Government Area, Ogun state, South-Western Nigeria. 1.3 STATEMENT OF THE PROBLEM It is almost customary in Africa, most especially the south-western region of Nigeria which the designated area of study is located that parents most especially mothers tend to narrow every assumption of illnesses to malaria or infestation of an intestinal parasite such as the roundworm. Reported unconfirmed cases of active and matured worms being seen in the feces of children and some adults had been a rampant recurrence in the Nigerian society. This infestation of children’s intestines with these parasitic helminths had been known to be causes of a larger amount of stomach ache and other helminthic infections symptoms. Though this seems much like myth despite the studies that have been carried out that proves that children in developing countries like Nigeria have a high tendency to get infected with 3 worms such as Ascaris lumbricoides as most parents still ignore the need to subject their children to the use of anthelminthic drugs. Also, such parents and guardians do not take their children and wards to the hospital for periodic checkups. It has been difficult in recent times to know how much people get infected with the worms periodically in the society. It is a major aim of this research project to identify how much children get infected with Ascaris lumbricoides. 1.3.1 TRANSMISSION OF ASCARIS LUMBRICOIDES The source of infection of the Ascaris lumbricoides is from objects and food which have been contaminated with fecal matter containing the ascaris eggs. Ingestion of such infective eggs from soil contaminated with human feces or contaminated vegetables and water is the primary route of infection. The infectious Ascaris lumbricoides eggs may occur on other objects such as hands, money, and furniture. Transmission from human to human by direct contact is impossible. Transmission comes through municipal recycling of wastewater into crop fields. This is quite common in emerging industrial economies and poses serious risks for local crop sales and exports of contaminated vegetables. Ascaris lumbricoides eggs are occasionally inhaled of contaminated dust. Children playing in contaminated soil may acquire the parasite via their hands. Co-infection with other parasite occurs with some regularity because of similar predisposing factors for transmission. 4 1.3.2 SYMPTOMS The symptoms accompanying the infection of Ascaris lumbricoides are diverse and they may include the following • Nausea • Vomiting • Abdominal discomfort • Abdominal cramping • Abdominal swelling (especially in children) • Fever • Irregular stools or diarrhea • Weight loss • Growth impairment in children due to malabsorption • Coughing and/or wheezing • Passing roundworms and their eggs in the stool In cases of Ascaris lumbricoides in the lungs; • Aspiration pneumonia (rare) • Blood in mucus • Chest discomfort 5 1.3.3 LIFE CYCLE OF Ascaris lumbricoides Life cycle of A. lumbricoides 1. Adult worms live in the lumen of the small intestine. 2 A female may produce up to 240,000 eggs per day, which are passed with the feces. 3 Fertile eggs embryonate and become infective after 18 days to several weeks, depending on the environmental conditions (optimum: moist, warm, shaded soil) 4 After infective eggs are swallowed, the larvae hatch; 5 The hatched larvae invade the intestinal mucosa, and are carried via the portal; 6 Then systemic circulation to the lungs. 7 The larvae mature further in the lungs within a span of 10-14 days; the matured larvae penetrate the alveolar walls, ascend the bronchial tree to the throat, and are swallowed. Upon reaching the small intestine, they develop into adult worms between 2 and 3 6 months are required from ingestion of the infective eggs to oviposition by the adult female. Adult worms can live 1 to 2 years. The found female worm in the intestine of the infected individual releases fertile ova which are excreted in the feces. The ova require a period of one to four weeks in the soil for embryonation to an infective state. They are very resistant to heat and cold but are relatively more sensitive to desiccation. Ova probably cannot survive for more than a few days in very arid conditions (Warren and Mahmoud, 1984) but can remain viable for up to seven years under optimal conditions of temperature and humidity (Croll et al, 1982), providing a long-term source of infection for persons who may ingest the ova by way of soiled hands, consumption of contaminated foods or by inhalation of ova present in dust. Ascaris lumbricoides is the largest nematode worm parasites living in human intestine. It’s cylindrical shape and red so-called roundworm. Male adult worm sized is 15-25 cm x 3 mm and female are 25-35 cm x 4 mm. Female worm can lay up to 200,000 eggs a day, which can last for her lifetime which is approximately 1-2 years. This worm eggs do not hatch in the human body but is release with the host feces. There are two types of worm eggs, fertilized and unfertilized. Fertilized eggs generally sized 60 x 45 microns, with fertilized-corticated have a cortex and fertilized-excorticated cortex does not have a cortex. Unfertilized egg is not fertilized yet, generally sized 90 x 40 microns and more oval and contains no embryo. 7 The action of bile salts and enteric juices of the small intestine (jejunum) on the ovum results in the liberation of the larva into the lumen of the gut. The larvae are about 260 um long by l4nm in diameter. From the lumen, they actively penetrate the intestinal wall to gain access to the hepatic portal circulation and the mesenteric lymphatics. From there, the larvae enter the inferior vena cava of the heart, continuing on ta the pulmonary vessels and the interalveolar tissues After a maturation process of 9-15 days duration, the larvae break into the alveolar spaces and are carried in the mucus secretions to the epiglottis from where they are swallowed, thereby being reintroduced to the gut. The larvae remain sequestered in the mucosa of the jejunum until maturation into adult male and female worms, when they move into the lumen where they live unattached. Radiological studies have shown that the majority of adults live in the Jejunum, outnumbering those found in the ileum (Makidono, 1956). The prepatent period, which is the time from infection until the female begins to 1ay eggs, is 8-12 weeks. The female may lay up to 250,00 eggs dai1y and reach a size from 15-45cm in 1ength by 5mm in diameter. The male reaches a maximum size of 25cm in length by 3mm in diameter and can be distinguished from the female by its characteristic curly tail. the 1ife expectancy of the adult worm is approximately one year. The diagnosis of ascariasis is made by the observation of typical ova in the stool of the infected individual. 8 Ascaris lumbricoides life cycle includes the processes of ascariasis transmission in humans. Eggs released by the worm through human feces will develop into infertile and fertile eggs. Fertile eggs will develop into embryos and infective larvae if the environment is suitable to growth. When infective form ingested by humans it will hatch into larvae in the small intestine. The larvae then exit through the wall into the circulatory system or lymphatic system. The larvae will go to the lungs, trachea, pharynx, esophagus and swallowing enter to the small intestine. In the small intestine the larvae turn into adults. A. lumbricoides life cycle lasts 2-3 months. 1.3.4 DIAGNOSIS The diagnosis of ascariasis is usually made up of stool microscopy. Other forms of diagnosis are through eosinophilia, imaging and ultra sound of serology examination. Microscopy: Characteristic eggs may be seen as direct examination of feces or following concentration techniques. Eggs do not appear in the stool for at least 40 days after infection, the main drawback of relying upon eggs in the feces as the sole diagnostic market for Ascaris lumbricoides infection is that an early diagnosis cannot be made, including during the phase of respiratory symptoms. In addition, no egg will be present in stool if the infection is due to make worms only. Sometimes, an adult worm is passed, usually per rectum, if Ascaris lumbricoides is found in the feces, a stool specimen can be checked for eggs to document whether an additional worm is present prior to instituting therapy. 9 Imaging: in heavily infected individuals, particularly children, large collection of worms may be deferrable in plain film of the abdomen. The mass of worm’s contrasts against the as in the bowel, typically producing a whirlpool of effects. Radiologic defects of detecting elongated filling defects following barium meal examinations of the small bowel. The warms also sometimes ingest barium, in which case the alimentary canal appears as a white thread bisecting the length of the worm’s body. Radiographs will also show when there is associated intestinal obstruction. Ultra sound: Ultra sound examinations can help to diagnose hepatobiliary or pancreative ascariasis. Single worms, bundles of worms, or a pseudo rumor or like appearance may be seen. Individual body segments of worms may be visible, and on prolonged scanning, the worms will show curling movements. Computed tomographic (CT) scanning or magnetic resonance imaging (MRI) may also be used to identify worms in the liver or bile ducts, but this is not usually necessary. Imaging the worm in cross-section gives a bull’s eye appearance. When ascariasis involving the biliary tree of pana creative duct is suspected, an ERCP will not only establish the diagnosis but also allow the direct removal of the worm. Serology: infected individuals make antibodies to Ascaris lumbricoides which can be detected. However, serology is generally reserved for epidemiologic studies rather than in 10