Ancylostomiasis Infections - Research Paper Example

? Ancylostomiasis Ancylostomiasis Introduction This paper looks into hookworm infections (Ancylostomiasis) in a detailed manner. In addressing the issue of hookworm infections, the paper will outline the natural history, epidemiology, treatment, symptoms, and prevention of hookworm infections. Over the last two decades, hookworm infections have attracted the attention of numerous physicians due to the adverse effects associated with these infections. Much of the negative effects that come along with hookworm infections are of more relevance in the developing world than in the first world countries. This phenomenon is as a result of factors such as poverty and poor sanitation, which are ranked among the key factors, which lead to the high prevalence of hookworm infections in the developing world. To date, efforts in reducing mobility as a result of hookworm infections have been directed towards massive deworming of school going children using benzimidazoles. Natural History Thorough scientific analysis of hookworm infection in human began in early twentieth century. From its inception to date, significant improvements in the understanding of hookworm infections are evident in nearly all regions of the world. There have been significant advances in molecular biology, which has contributed immensely in the identification of various molecules present in hookworms that are of significant importance in the molecular pathogenesis of Ancylostomiasis or understanding of host-parasite relationship. In addition, identification of such molecules offers immense promises in the quest to develop vaccines against hookworms. However, it is worth mentioning that little is known regarding host immune responses towards hookworm infections, but experts have noted that hookworms have the potential to trigger certain immune responses to vaccines and other pathogens (Blaxter, 2000). Understanding the pathophysiology and epidemiology of hookworm infections in humans has been a concern for the last one hundred years. The first work in the understanding of hookworm infections was documented by Theodore Bilharz who associated intestinal helminths with tropical chlorosis. In early 20th century, the lifecycle of A. duodenale was documented, which was later followed by the discovery of N. amercanus in the western hemisphere. The public health relevance of hookworm infections caught the attention of medical experts in 1901 following the death of close to 12,000 persons in Puerto Rico Island. Following this revelation, the United States formed the Rockefeller Sanitary Commission with an aim to combat hookworm infections. In addition, the International Health Commission was founded to address hookworm infections overseas (Blaxter, 2000). Hookworms are nematodes that belong to Ancylostomatidae family. Within this family, there are two main genera that are of relevance to human beings. The genera include Necator and Ancylostoma and are distinguished by the presence of teeth or cutting plates that are present in adult parasite buccal capsule. In the genera Necator, the only species that are of relevance to a human being is Necator americanus. However, on several occasions the species has been identified from non-human primates. The pig is considered to be the intermediate host for N. americanus. In genera Ancylostoma, the only species of relevance to human infections is the Ancylostoma duodenale (Nelson & Williams, 2007). The lifecycle and transmission of hookworms in humans is not complicated at all. Humans get hookworm infections after the infective Laval stage present in the soil penetrate through the skin or are ingested via contaminated food or other means. Continued studies reveal that the L3 of N. amercanus has the potential to invade the epithelial lining of the buccal cavity when ingested through the mouth. The L3 can survive in the soil for quite some time when there is appropriate warmth, moisture, and shade. After the invasion, the L3 is signaled to resume its development and secret bioactive polypeptides (Behnk et al, 2002). After the activation of L3, the activated Laval stage migrates via the vasculature where they are swept through the afferent circulation to the right region of the heart and later to the pulmonary vasculature. The L3 later break out of lung capillaries and move into the lung parenchyma where they move up the alveoli, bronchioles, bronchi, and trachea. After reaching the trachea, the L3 is coughed and swallowed, which marks the beginning of a new stage with the gastrointestinal tract. Within the gastrointestinal tract, the L3 molt twice, leading to the development of an adult parasite. Attaining sexual maturity may take 5-8 weeks from the time of L3 infection and females can produce thousands of eggs daily (Nelson & Williams, 2007). Epidemiology Continued research work reveals that children can suffer from hookworm infections as early as 6 months of age. Subsequently, the prevalence of hookworm infections increases with age and attains a plateau phase at adulthood. Studies conducted in China and Southeast Asia suggest that the highest prevalence is evident in the middle aged or at times in persons over the age of 60 years (Bundy et al, 2002). The most worrying phenomenon is the fact that the elderly are at a risk of getting hookworm infections, especially in the developing world. It has also been suggested that males are at an increased risk of getting hookworm infections compared to their female counterparts. This is attributed to variations in exposure between the two sexes rather than variations in susceptibility to infection (Nelson & Williams, 2007). One reason why males are more prone to hookworm infections than females is due to their increased involvement in chores, which entail the use of soils contaminated with hookworms. It is estimated that close to 2 billion people are infected with blood sucking hookworms. Among the infected persons, over 2 million people are believed to suffer from significant anemia and over 65, 000 of the infected persons die annually (Behnk et al, 2002). Symptoms Hookworm infections come along with numerous symptoms, which are either mild or severe. One of the most symptoms is the cutaneous syndrome referred to as the ground. This symptom occurs as a result of skin breaks that arise when L3 penetrates the through the skin. The ground itch is commonly experienced on the hands and feet. The other symptoms of hookworm infection include cough, sore throat and fever, which arise as a result of L3 migration via the respiratory tract. Pulmonary hookworm infections are similar to Loeffler’s pneumonitis due to the presence of eosinophils. Presence of L3 in the gastrointestinal tract causes epigastric pain and other gastrointestinal symptoms such as nausea and flatulence (Cook & Zumla, 2009). Migration of the L3 through the buccal cavity can lead to Wakana disease, which is a syndrome characterized by hoarseness, vomiting, cough, nausea, and pharyngeal irritation. Anemia is perhaps the most severe symptom in times of hookworm infection due to increased blood loss to hookworms. During the process of blood sucking, hookworms cause perforations on the intestinal walls, which interfere with the functioning of the intestines (Cook & Zumla, 2009). Treatment The commonly used drugs in the treatment of hookworm infections include the benzimidazole anthleminthics due to their wide range of action, high efficacy, low cost, and ease of administration. These drugs have gained popularity in poor nations that lack expensive sanitation amenities. The four main anthleminthics in use for the treatment of hookworms include pyrantel pamote, levamisole, mebendazole, and albendazole. Vaccines are also under development to help in the fight against hookworm infections (Bennett & Guyatt, 2000). Control measures Initially, the main objectives in the control of hookworm infections included total eradication of the infections. However, increased poverty and poor sanitation proved that it is difficult to eradicate hookworm infections due the high transmission rate of hookworms (Bennett & Guyatt, 2000). The current efforts aim at reducing the mortality rate from hookworm infections. This is done through the use of chemotherapies, in conjunction with health education, use of clean water, and proper sanitation. Improved sanitation and hygiene can be regarded as the essential measures in the establishment of long-term strategies in the control of hookworms. Increase d usage of latrines for the disposal of human waste is a leading factor that reduces the prevalence of hookworm infections. Other measures include increased campaign regarding the use of footwear to prevent the penetration of hookworm through the feet (Cook & Zumla, 2009). References Behnk, J.M, De Clercq, D., Sacko,M., Gilbert, F.S., Ouattara, D.B., & Vercruysse, J. (2002). The epidemiology of human hookworm infections in the southern region of Mali. Tropical Medicine and International Health, 5(5), 343–354. Bennett, A., & Guyatt, H. (2000). Reducing intestinal nematode infection: efficacy of albendazole and mebendazole. Parasitology Today, 16(2), 71–74. Blaxter, M. (2000). Genes and genomes of Necator americanus and related hookworms. International Journal of Parasitology, 30(4), 347–355 Bundy, P., Michael, E., & Guyatt, H. L. (2002). Epidemiology and control of nematode infection and disease in humans: the Biology of Nematodes. London: Taylor and Francis. Cook, G. & Zumla, A. I. (2009). Manson's Tropical Diseases: Expert Consult. New York: Elsevier Health Sciences. Nelson, K.& Williams, C. M. (2007). Infectious Disease Epidemiology: Theory And Practice. New York: Jones & Bartlett Learning. Read More