6 Conclusions and recommendations
6.1 Conclusions
6.1.3 Performance
1. A large scale multicentre study to further demostrate the relationship between hookworm and asthma symptom.
2. Determination of the immunological response of asthmatics to the various helminths (i.e.
quantification of levels helminth induce antibodies, serum eosinophil and other specific markers such as interleukins and interferon) to establish the possible pathogenesis for the relationship of asthma and the worms.
82
LIMITATIONS OF STUDY
1. The cross-sectional design, did not allow the researcher to make causal inferences. Further confounding factors may not be equally distributed between groups. However, the researcher performed statistical analysis taking into account the confounding factors identified in the subjects.
2. The use of questionnaires to access information on the presence of asthma symptoms, its risk factors and association with helminths were the major limitations of this study. The use of questionnaires makes the study open to information bias since it depends on the response of those interviewed. Therefore, misclassification of exposure may have occurred in the present study. The researcher used video questionnaire to limit the misconception on asthma symptoms that might have arisen. Further, the questionnaire was pretested before it usage to reduce the chances that may lead to miss information.
3. The stool sample was collected only once from the students, this may have reduced the true prevalence of intestinal helminthic infestation as multiple sample collection may have increased the number of students who might have been infected with helminths.
4. The inability to do viral studies on the subjects with history of wheezing to identify those whose symptom may be due to viral illness. This was mainly due to lack of the laboratory facilities for viral studies in Abuja.
5. Other asthma symptoms such as chest tightness that could not be demonstrated in the video questionnaire were not obtained. This may have increased the student population with asthma symptoms.
83
REFERENCES
1. Masoli M, Fabian D, Holt S, Beasley R. The global burden of asthma: executive summary of the GINA Dissemination Committee Report. Allergy 2004; 59: 469-78.
2. Vanschayck CP, Smith HA. The prevalence of asthma in children: a reversing trend. Eur Respir J. 2005; 26: 647-50.
3. Braman SS. The global burden of asthma. Chest. July 2006; 130: 4S-12S.
4. Bousquet J, Bousquet PJ, Godard P, Daures JP. The public implication of asthma. Bull WHO.
2005; 83: 548-54.
5. Oluwole O, Arinola OG, Falade GA, Ige MO, Falusi GA, et al. Allegy sensitization and asthma among 13-14 year old school children in Nigeria. Afri Health Sci. 2013; 13: 144-53.
6. Sengler C, Lau S, Wahn U, Nickel R. Interaction between gene and environmental factors in asthma and atopy: new developments. Respiri. Res 2002; 3: 1-15.
7. Romagnani S. T-cell subsets (Th1 versus Th2). Ann Allergy Asthma Immunol. 2000; 85:9-18.
8. Grove DI. What is the relationship between asthma and worms? Allergy.1982; 37:138-48.
9. Lynch NR, Palenque M, Hagel I, Diprisco MC. Clinical improvement of asthma after antihelminthic treatment in a tropical situation. AmJ Respir Crit Care Med. 1997; 56: 50-4.
10. Leonardi-Bee J, Pritchard D, Brilton J. Asthma and current intestinal parasite infection:
systematic review and meta-analysis. AmJ Respir Crit Care Med. 2006; 176: 514-23.
11. Cooper PJ. Can Intestinal Helminth Infections (geohelminths) affect the development and expression of asthma and allergic diseases? Clin Exp Immunol. 2002; 128: 398-404.
12. Lau S, Matricardi PM. Worm, Asthma, and Hygiene hypothesis. The Lancet 2006; 367: 1554-58.
84
13. Falcone FH, Pritchard DI. Parasite role reversal: worms on trial. Trends Parasitol, 2005; 21:
157-60.
14. Grove DI, Burston TO, Forbes IJ. Immunoglobin E and eosinophil level in atopic and non-atopic populations infested with Hookworm. Clin. Allergy 1974; 70: 1-10
15. World Health Organization. Eliminating soil transmitted helminthiasis as a public health problem in children: progress report 2001- 2010 and strategic plan 2011- 2020. WHO library cataloguing in publication data. WHO 2012. ISBN: 9789241503129.
16. Finkelman FD, Shea-Donohue T, Goldhill J, Sullwan GA, Morris Sc et al. Cytokine regulation of host defence against parasitic gastrointestinal nematodes: lesson from studies with Rodent models. Annul. Rev immunol. 1997; 15: 505-33.
17. Gause WC, Urban JF, Stadecker MJ. The immune response to parasitic helminths: insights from murine models. Trends Iimmunol. 2005; 24: 269-77.
18. Ozoh OB, Bandele EO. A synopsis of asthma research in Nigeria between 1970 and 2010.
AJRM. 2012; 7: 5-11.
19. Janson C, Anto J, Burney P, Chinn S, DeMarco R, et al. The European Community Respiratory Health Survey: What are the main results so far? Eur Respir J. 2001; 18: 598 – 611.
20. Newman TA. Asthma. In: Warrell DA, Cox TM, Firth JD, Benz EJ. (Eds.) Oxford textbook of medicine. 4th edn. Oxford: Oxford University Press; 2003: Section 17.4.4
21. EPR3. “Expert Panel Report: Guideline for the Diagnosis and Management of Asthma (EPR3 full report 2007)”. NIH Publication No. 07-4051. Bethesda. MD: U.S. Department Of Health And Human Services. National Institute of Health; National Heart, Lung and Blood Institute;
National Asthma Education and Prevention Program, 2007.
85
22. World Health Organization (WHO), Global Surveillance Prevention And Control Of Chronic Respiratory Disease: A Comprehensive Approach, 2007.
Link: http://l2www.who.int/gard/publications/GARD%20Book%202007.pdf (Accessed 03/01/2013)
23. Ahmed PA, Olumukoro CN, Ulonnam C, Ballong J. The burden of childhood asthma and its management as seen at the National Hospital, Abuja. Archives of Nigerian Medicine and medical science 2011;8:9-17
24. Onazi SO, Orogade AA, Yakubu AM. Exercise induce bronchospasm among school children in Gusau, Nigeria. WAJM 2012; 31: 76-80.
25. Oviawe O. Asthma in children. In: Azubuike JC, Nkanginieme KEO (editors). Paediatrics and Child Health in a tropical region. 2nd edition. Owerri. African educational services. 2007:
460–8.
26. Oviawe O. Prevalence and pattern of childhood asthma in a rural community in Nigeria. Afr Child Health J 1999; 1: 8–14.
27. Abubakar A. Prevalence of asthma among primary school children in Zaria (dissertation), West African College of Physicians, Faculty of Paediatrics, April 2000.
28. Asher MI, Keil U, Anderson HR, Beasley R, Crane J, et al. International study of asthma and allergies in childhood (ISAAC): rationale and methods. Eur. Respr. J. 1995; 8: 483-91.
29. Beasley R. worldwide variation in prevalence of symptoms of asthma, allergic rhinoconjuctivitis, and atopic eczema: ISAAC. The Lancet 1998; 351: 1225-32.
30. Falade AG, Ige OM, Yusuf BO, Onadeko MO, Onadeko BO. Trends in the prevalence and severity of symptoms of asthma, allergic rhinoconjunctivitis, and atopic eczema. J. Natl Med Assoc 2009; 101:414- 8.
86
31. Guill MF. Asthma update: Epidemiology and pathophysiology. Pediatr Rev. 2004; 25: 299- 305.
32. Tippets B, Guilbert TW. Managing Asthma in Children: Part 1: Making the Diagnosis, Assessing Severity. Consultant for Pediatricians, 2009; 8:168-74.
33. Bijanzadeh M, Mahesh PA, Ramachandra NB. An understanding of the genetic basis of asthma. Indian J Med Res, 2011; 134: 149-61.
34. World Health Organization (WHO). Genetics and asthma. Available from: Link:
http://www.who.int/genomics/about/Asthma.pdf. (Accessed 03/01/2013)
35. Postma DS. Gender differences in asthma development and progression. Gend Med.
2007;4:133-46.
36. Fireman P. Understanding asthma pathophysiology. Allergy Asthma Proc. 2003; 24:79-83.
37. Oviawe O. Childhood asthma in Benin. Niger J Paed 1986;13:141-5
38. Ibe CC, Ele UP. Prevalence of bronchial asthma among adolescents in Anambra State, Nigeria. Nig J Int Med 2002; 5: 23–6.
39. Salami AK, Olugoyo PO. Bronchial asthma in Ilorin: a five year review. Trop J Health Sci 2004; 11: 19–23.
40. Liu AH, Covar RA, Spahn JD, Leung DYM. Childhood asthma. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF (editors). Nelson textbook of paediatrics, 19th ed. Saunders, Elsevier Inc. 2007;780-801.
41. Pekkanen J. Pearce N. Defining asthma in epidemiological studies. Eur Respr J 1999; 14: 951-7.
42. Van-Aalderen WM. Childhood Asthma: Diagnosis and treatment. Scientifica 2012; 674204:1-18
87
43. Weller PF, Nutman TB. Intestinal nematodes. In: Fauci AS, Braunwald E, Kasper DL, Hauser SL, Longo DL, et al. editor(s). Harrison‟s Principles of Internal Medicine. New York:
McGraw-Hill, 2008:1739–44.
44. Strickland GT. General principles. In: Strickland GT editor(s). Hunter‟s Tropical Medicine and Emerging Infectious Diseases. 9th Edition. Philadelphia, PA: Saunders, 1999: 713–6.
45. Finch RG, Irving WL, Moss P, Anderson J. Infectious diseases, tropical medicine and sexually transmitted infection. In: Kumar P, Clark M editor(s). Kumar and Clark‟s Clinical Medicine.
7th Edition. London: Saunders, 2009:79–206.
46. Olano JP, Weller PF, Guerrant RL, Walker DH. Principles of parasitism: host-parasite interaction. In: Guerrant RL, Walker DH,Weller PF editor(s). Tropical Infectious Diseases:
Principles, Pathogens and Practice. 2nd Edition. London: Churchill Livingstone, 2006:1–12.
47. Anosike JC, Zaccheaus VO, Adeiyongo CM, Abanobi OC, Dada EO, et al. Study on the intestinal worm infestation in a central Nigerian rural community. J Appl sci Environ Management 2006; 10: 61- 6.
48. Egwunyenga OA, Ataikiru DP. Soil transmitted helminthiasis among school age children in Ethiope East Local Government Area, Delta state, Nigeria. Afr J Biotechnol 2005; 4: 938 –41.
49. Meremikwu MM, Antia-Obong OE, Asindi AA, Ejezie GC. Prevalence and intensity of intestinal helminthiasis in preschool children of peasant farmers in Calabar, Nigeria. Niger J Med 1995; 2:40 – 4.
50. Adefioye OA, Efushile AM, Ojurongbe O, Akindele AA, Adewuyi IK, et al. Intestinal helminthiasis among school children in Ilie, Osun state, South West Nigeria. Sierra Leone J Biomed Res 2011; 3: 36 – 42.
88
51. Ilechukwu GC. Pattern of Intestinal helminthiasis in children aged 1- 10 years in Enugu, Nigeria. A dissertation submitted to the Faculty of Paediatrics, National Postgraduate Medical College of Nigeria. May 2005.
52. Damen JG, Luka J, Biwan GI, Lugos M. Prevalence of Intestinal parasites among pupils in rural North Eastern Nigeria. Niger Med J 2011; 52: 4 – 6.
53. Nock H, Duniya D, Galadima M. Geohelminth eggs in the soil and stool of pupils of some primary schools in Samaru, Zaria, Nigeria. The Niger J Parasitol 2003; 24: 115 – 22.
54. Adanyi CS, Audu PA, Luka SA, Adanyi DN. The impact of health education on the prevalence of helminthiasis in primary school children in Zaria, Kaduna state. Scholars research library. Arch Appl Sci Res 2011; 3: 6 – 11.
55. Bachuta E, Zenaidi N, Belkaid M, Tabet- Derraz O. Evaluation of intestinal parasitoses detected among Algerians (1984- 88). Bull Soc. Pathol Exot 1984-88; 83: 51- 60.
56. Bundy DAP, Gujatt HL. Schools for health focus on health, education and the school age child. Parasitol Today 1996; 12: 1- 16.
57. Hotez PJ, Pritchard DI. Hookworm infection. Sci Am 1995; 272: 68- 74.
58. Behnke JM, Declerq D, Sacko M, Quattara DB, Vercrysse J. The epidemiology of human hookworm infections in the Southern region of Mali. Trop Med Int Health 2000; 5: 343- 54 59. Ogbe MG, Odudu LA. Gastrointestinal helminthiasis in primary schools in Epe Local
Government Area, Lagos state, Nigeria. Nig J Parasitol 1988 – 90; 9 – 11: 95 – 106.
60. Ransom BH, Foster, WD. Observations on the life history of ascaris lumbricoides. U S. Dept.
Agr. Bui. 1920; 817:1-47.
61. Tullis DCH. Bronchial asthma associated with intestinal parasites. The N Engl J. Med, 1970;
282: 370-2.
89
62. Hagel I, Cabrera M, Hurtado MA, Sanchez P, Puccio F, Di Prisco MC, et al. Infection by Ascaris lumbricoides and bronchial hyperreactivity: an outstanding association in Venezuelan school children from endemic areas. Acta Trop. 2007;103:231–41.
63. Palmer LJ, Celedon JC, Weiss ST, Wang B, Fang Z, Xu X. Ascaris lumbricoides infection is associated with increased risk of childhood asthma and atopy in rural China. Am J Respir Crit Care Med. 2002; 165:1489 –93.
64. Joubert JR, de Klerk HC, Malan C. Ascaris lumbricoides and allergic asthma: a new perspective. S Afr Med J. 1979;56:599–602
65. Joubert JR, van Schalkwyk DJ, Turner KJ. Ascaris lumbricoides and the human immunogenic response: enhanced IgE-mediated reactivity to common inhaled allergens. S Afr Med J.
1980;57:409–12.
66. Patterson R, Harris KE, Pruzansky JJ. Induction of IgE-mediated cutaneous, cellular, and airway reactivity in rhesus monkeys by Ascaris suum infection. J Lab Clin Med.
1983;101:864–72.
67. Caraballo L. New allergens of relevance in tropical regions: The impact of Ascaris Lumbricoides infections WAO journal 2011;4:77-84
68. Turton JA. IgE, parasites, and allergy. Lancet 1976; 2: 686-7.
69. Huang SL, Tsai PF, Yeh YF. Negative association of Enterobius infestation with asthma and rhinitis in primary school children in Taipei. Clin Exp Allergy 2002; 32 :1029–32.
70. Medeiros M Jr, Figueiredo JP, Almeida MC, Matos MA, Araújo MI, et al. Schistosoma mansoni infection is associated with a reduced course of asthma. J. Allergy and Clin Immunol 2003; 111:947–51.
90
71. Cardoso LS, Costa DM, Almeida MCF, Souza RP, Carvalho EM et al. Risk Factors for Asthma in a Helminth Endemic Area in Bahia, Brazil. J. Parasitol Res. 2012; Article ID 796820:1-8
72. Cooper PJ, Chico ME, MD, Rodrigues LC, Ordonez M, Strachan D et al. Reduced risk of atopy among school-age children infected with geohelminth parasites in a rural area of the tropics J Allergy Clin Immunol 2003;111:995-1000.
73. Bragagnoli G, Silva MTN. Ascaris lumbricoides infection and parasite load are associated with asthma in children. J Infect Dev Ctries 2014; 8:891-7.
74. Erb KJ. Can helminths or helminth-derived products be used in humans to prevent or treat allergic diseases?. Trends Immunol 2008;30:75–82.
75. Feary J, Venn A, Brown A, Hooi D, Falcone FH, et al. Safety of hookworm infection in individuals with measurable airway responsiveness: a randomized placebo controlled feasibility study. Clin Exp Allergy 2009; 39:1060–8.
76. Feary JR, Venn AJ, Mortimer K, Brown AP, Hooi D, et al. Experimental hookworm infection:
a randomized placebo-controlled trial in asthma. Clin Exp Allergy 2010; 40: 299-306
77. Bager P, Arnved J, Ronborg S, Wohlfahrt J, Poulsen LK, et al. Trichuris ova therapy for allergic rhinitis: a randomized, double-blind, placebo-controlled clinical trial. J. Allergy Clin Immunol 2010; 125:123–30.
78. Daveson JA, Jones DM, Gaze S, McSorley H, Clouston A, et al. Effect of hookworm infection on wheat challenge in celiac disease - a randomised double-blind placebo controlled trial.
PLoS One 2011; 6:1–9.
91
79. Woolcock AJ, Colman MH, Jones MW. Atopy and bronchial reactivity in Australian and Melanesian population. Clin. Allergy 1978; 8:155-64
80. Tsuji N, Miyoshi T, Islam MK, Isobe T, Yoshihara S, et al. Recombinant Ascaris 16-Kilodalton protein-induced protection against Ascaris suum larval migration after intranasal vaccination in pigs. J Infect Dis. 2004;190:1812–20.
81. Islam MK, Miyoshi T, Tsuji N. Vaccination with recombinant Ascaris suum 24-kilodalton antigen induces a Th1/Th2-mixed type immune response and confers high levels of protection against challenged Ascaris suum lung-stage infection in BALB/c mice. Int J Parasitol.
2005;35:1023–30.
82. Salako LA, Sofowora, EO. Bronchial asthma associated with intestinal parasites. N Engl J.
Med, 1970; 283: 264-5.
83. Warrell, DA, Fawcett, IW, Harrison, BD, Agamah, AJ, Ibu, JO, et al. Bronchial asthma in the Nigerian savanna region. A clinical and laboratory study of 106 patients with a review of the literature on asthma in the tropics. Q. J. Med, 1975; 44: 325-47.
84. Turner JD, Jackson JA, Faulkner H, Behnke J, Else KJ, et al. Intensity of intestinal infection with multiple worm species is related to regulatory cytokine output and immune hyporesponsiveness. J Infect Dis. 2008;197:1204 –12.
85. van den Biggelaar AH, van Ree R, Rodrigues LC, Lell B, Deelder AM, Kremsner PG, Yazdanbakhsh M. Decreased atopy in children infected with Schistosoma haematobium: a role for parasite-induced interleukin- 10. Lancet. 2000;356:1723–27.
86. Holt PG. Parasites, atopy, and the hygiene hypothesis: resolution of a paradox? Lancet.
2000;356:1699 –1701.
92
87. Cooper PJ, Chico ME, Bland M, Griffin GE, Nutman TB. Allergic symptoms, atopy, and geohelminth infections in a rural area of Ecuador. Am J Respir Crit Care Med. 2003;168:313–
7.
88. Yazdanbakhsh M, Matricardi PM. Parasites and the hygiene hypothesis: regulating the immune system? Clin Rev Allergy Immunol. 2004; 26:15–24.
89. Scrivener S, Yemaneberhan H, Zebenigus M, Tilahun D, Girma S, Ali S, et al . Independent effects of intestinal parasite infection and domestic allergen exposure on risk of wheeze in Ethiopia: a nested case–control study. Lancet 2001;358: 1493–9.
90. Bateman ED, Hurd SS, Barnes PJ, Bousquet J, Drazen JM, et al. Global strategy for asthma management and prevention: GINA executive summary. Eur Respir J 2008; 31: 143-78.
91. Adeniyi BO, Erhabor GE. The peak flow meter and it use in clinical practice. AJRM 2011;
review article: 5-8.
92. Lukrafka LJ, Fuchs SC, Moreira LB, Picon RV, Fischer GB, Fuchs FD. Performance of ISAAC questionnanaire to establish the prevalence of asthma in adolescents: a population based study.J. Asthma 2010; 47:166–9.
93. Lai CK, Chan JK, Chan A, Wong G, Ho A, et al. Comparison of the ISAAC video questionnaire (AVQ3.0) with the ISAAC written questionnaire for estimating asthma associated with bronchial hyperreactivity. Clin Exp Allergy. 1997; 27:540-5.
94. Fuso L, de Rosa M, Corbo GM, Valente S, Forastiere F, et al. Repeatability of the ISAAC video questionnaire and its accuracy against a clinical diagnosis of asthma. Respir Med. April 2000; 94:397-403
95. Federal Ministry of Health, Standard treatment guideline- Bronchial Asthma. FMOH 2008 p 166-7.
93
96. Pearson RD, Schwartaman JD. Nematodes limited to the intestinal tract. In: Strikland GT (editor). Hunder‟s Tropical Medicine. Philadelphia WB Saunders; 1991: 689 – 96.
97. Cheesebrough M. Techniques used to identify parasites. In: Cheesebrough M (editor). Medical Laboratory Manual for tropical countries. 2nd ed. Cambridge: University press; 199:.178 – 93.
98. Suzuki N. Diagnostic method in intestinal helminthic infection: collected papers on the control of soil transmitted helminthiasis. The Asian Parasite Control Organisation (APCO) Research Group 1980; 1:25 – 35.
99. World health organization: Basic laboratory method in Medical parasitology. WHO 1991: 67-70.
100. Endris M, Tekeste Z, Lemma W, Kassu A. Comparison of the Kato-Katz, Wet Mount, and Formol-Ether Concentration Diagnostic Techniques for Intestinal Helminth Infections in Ethiopia ISRN Parasitology 2013; 180439: 1-5.
101. Blotkamp J, Krepel HP, Kumar V, Baeta S, Van‟t Noordende JM, Polderman AM.
Observations on the morphology of adults and larval stages of Oesophagostomum sp. isolated from man in northern Togo and Ghana. J Helminthol 1993;67: 49–61.
102. Krepel HP, van der Velde EA, Baeta S, Polderman AM. Quantitative interpretation of coprocultures in a population infected with Oesophagostomum bifurcum. Trop Geogr Med 1995; 47: 157–159.
103. Odongo-Aginya EI, Kabatereine N, Ludwig S, Wabinga H; Fenwick A et al. Substitution of Malachite Green with Nigrosin - Eosin Yellow Stain in the Kato-Katz method: microscopical appearance of the helminth eggs. Afr Health Sci 2007; 7: 33-6
104. Bethony J, Brooker S, Albonico M, Geiger SM, Loukas A, et al. Seminar soil transmitted helminth infections: ascariasis, trichuriasis and hookworm. Lancet 2006; 367:1521-32
94
105. Ekundayo OJ, Aliyu MH, Jolly PE. A review of intestinal helminthiasis in Nigeria and the need for school – based intervention. J Rural and Trop Public Health 2007; 6: 33 – 9.
106. Albonico M. Ramsan M, Wright V, Jape K, Haji HJ, et al. Soil transmitted nematode infections and Mebendazole treatment in Mafia Island School children. Ann Trop Med Parasitol 2002; 96: 717 – 26.
107. Adams VJ, Lombard CJ, Dhansy MA, Markus MB, Fincham JE. Efficacy of Albendazole against the whipworm, Trichuris trichiura: a randomised controlled trial. S Afr Med J 2004; 94:
972 – 6.
108. Abuja. Online article web link:http//:www.fct.gov.ng/fct (Accessed 3/01/2013)
109. State in Nigeria. Online article. Web link: http//:www.nigerianbern.org/state. (Accessed 3/01/2013)
110. Abuja weather and climate. Online article available from:
web link; http//www.abujacity.com/abuja_and_beyond/climate-and-weather.html.
(Accessed 3/01/2013)
111. Nigerian Population Commission, in the Federal Government Official Gazette 2007; 96: 1342.
112. Federal Capital Territory Administration Education Secretariat. Annual school census statistical report 2010/2011.
113. Bartlett JE, Kotrlik JW, Higgins CC. Organizational Research: Determining Appropriate Sample Size in Survey Research. Inf. Technol 2001; 19; 43-50
114. Onwasigwe C. Simple Random Sampling Method. In: Onwasigwe C (editor). Principles and methods of epidemiology. Enugu Institute for Development Studies (publishers); 2004: 103 – 5.
95
115. Simoes SdM, da Cunha SS, Cruz AA, Dias KC, Alcantara-Neves NM, Amorim LD, et al A Community Study of Factors Related to Poorly Controlled Asthma among Brazilian Urban Children. PLoS ONE . 2012; 7: e37050
116. Oyedeji GA. Socio-economic and cultural background of hospitalized children in Ilesha. Nig J Paediatr 1985; 12: 111-7.
117. Faniran AO, Peat JK, Woolcock AJ. Prevalence of atopy, asthma symptoms and diagnosis, and the management of asthma: comparison of an affluent and a non-affluent country. Thorax 1999;54:606–10
118. Musa BM, Aliyu MD. Asthma prevalence in Nigerian adolescents and adults: systematic review and meta-analysis. AJRM 2014;10:4-9
119. Boechat JL, Rios JL, Sant'Anna CC, Franca AT. Prevalence and severity of asthma symptoms in school-age children in the city of Duque de Caxias, Rio de Janeiro, Brazil. J. Bras.
Pneumol. 2005; 31: 111-7.
120. Strachan DP, Limb ES, O'Neill AO, Wells N. A national survey of asthma prevalence, severity and treatment in Great Britain. Arch Dis Child 1994; 70: 174–8.
121. Henriksen AH, Holmen TL, Bjermer L. Gender differences in asthma prevalence may depend on how asthma is defined. Respir Med 2003;97:491–7.
122. Nicolai T, Pereszlenyiova-Bliznakova L, Illi S, Reinhardt D, Von Mutius E. Longitudinal follow-up of the changing gender ratio in asthma from childhood to adulthood: role of delayed manifestation in girls. Pediatr Allergy Immunol 2003;14:280–3.
123. Anderson HR, Pottier AC, Strachan DP. Asthma from birth to age 23: incidence and relation to prior and concurrent atopic disease. Thorax 1992;47:537–42.
124. Venn A, Lewis S, Cooper M, Hill J, Britton J. Questionnaire study of effect of sex and age on the prevalence of wheeze and asthma in adolescence. BMJ 1998;316: 1945–6.
96
125. Akinbami LJ, Moorman JE, Bailey C, Zahran HS, King M, et al. Trends in asthma prevalence, health care use, and mortality in the United States, 2001–2010. NCHS data brief, no 94.
Hyattsville, MD: National Center for Health Statistics. 2012.
126. Garba BI, Ibrahim M, Johnson A-WBR. Socio-demographic and clinical characteristics of asthmatic children seen at Aminu Kano Teaching Hospital, Kano, Nigeria. Niger J Paed 2014;41:360-4
127. Ernst P, Demisse K, Joseph L, Locher U, Becklake MR. Socioeconomic status and indicators of asthma in children. Am J Respir- Crit Care Med 1995;152:570-5.
128. Poyser MA, Nelson H, Ehrlich RI, Bateman D, Parnel DS, et al. Socioeconomic deprivation and asthma prevalence and severity in young adolescents Eur Respir J 2002; 19: 892–8
129. Aderele WI. Bronchial asthma in Nigerian children. Arch Dis childhood. 1979; 54: 448-453.
130. Hotez PJ, Brindley PJ, Bethony MJ, King CH, Pearce EJ, Jacobson J. Helminth infections: the great neglected tropical diseases. J. Clin. Invest. 2008;118:1311-21
131. Taylor-Robinson DC, Maayan N, Soares-Weiser K, Donegan S, Garner P. Deworming drugs for soil-transmitted intestinal worms in children: effects on nutritional indicators, haemoglobin, and school performance. Cochrane Database of Systematic Reviews 2015;7:
CD000371.
132. Gyorkos TW, Maheu-Giroux M, Blouin B, Casapia M. Impact of health education on soil-transmitted helminth infections in schoolchildren of the Peruvian Amazon: a cluster-randomized controlled trial. PLoS Negl Trop Dis. 2013;12;7(9):e2397
133. Grimes JE, Tadesse G, Mekete K, Wuletaw Y, Gebretsadik A, French MD, et al. School Water, Sanitation, and Hygiene, Soil-Transmitted Helminths, and Schistosomes: National Mapping in Ethiopia. PLoS Negl Trop Dis. 2016 8;10:e0004515.