Cholera and Typhoid Fever

Question: Cholera and Typhoid fever: Is there a misleading similarity? Answer: Introduction Cholera and Typhoid fever are major public health problems especially in developing countries as well as developed world. In 2016 more than five million people suffered from cholera and typhoid fever. Mortality due to cholera and typhoid fever occurs usually due to loss of fluid and secondary complications respectively. While they both are caused by bacterial infections and transmitted by the faeco oral route (from faeces to mouth) they are in truth, very dissimilar in various aspects. So, although cholera and typhoid fever are caused by bacteria and both microbes share similar transmission route, the people infected by cholera and typhoid fever exhibit different symptoms, affects different organ systems, have difference in the pathogenesis of disease and have different treatment regimen.This essay addresses the differences and similarities between cholera and typhoid fever on the basis of etiology, transmission, pathogenesis, symptoms, diagnostics, treatment, prevention and control. Body Both cholera and typhoid fever are diseases caused by bacteria. Vibrio cholerae serotype O1 and serotype O139 synonym Bengal causes cholera and Salmonella enterica serovar Typhi causes typhoid fever (WHO, 2008; WHO 2010). A similar but often less severe form of typhoid fever, paratyphoid fever, is caused bySalmonellaParatyphi A, B or C. Vibrio are small, gram-negative comma shaped rods, having single polar flagellum whereas Salmonella are gram-negative motile straight rods. Cholera and typhoid fever are transmitted by faecally contaminated food or water, by the faeco-oral route. The faeco oral route means pathogen can spread directly from contaminated hands touching the mouth and transmitting the pathogen directly :direct transmission; orthrough eating or drinking food or water contaminated with the infectious agents, or using utensils washed with contaminated water, ie indirect transmission. As both cholera and typhoid fever are diseases caused due to contamination in drinking wate r, poor personal hygiene and lack of sanitation, the incidence of them in Australia is limited. In Australia typhoid fever (approx. 150 cases each year in comparison to 21 million cases world wide) (Basnayat et al, 2005) and cholera (and even lesser in comparison to a total of 172454 cases worldwide) (NNDSS, 2010) are both predominantly travel related disease with more frequency in people travelling from the Indian subcontinent (Dale, et al, 2010) Cholera is an enteric disease (affects the gut) where as typhoid is a systemic infection (spread throughout) due to difference in their pathogenesis. When the bacteria Vibrio cholerae enters the intestine it releases cholera toxin which enters the enterocytes.On its entry in the enterocyte, the toxin induces adenylate cyclase to produce cAMP.The increased generation of cAMP stimulates cystic fibrosis transmembrane conductance regulator (CFTR), resulting in excretion of excess water and ions from entrocytes causing watery diarrhea.In case o f typhoid fever, S. typhi penetrate the enterocytes and then enter the macrophages. In these phagocytic cells S.typhi replicates before being released into the bloodstream which produces a systemic infection (Todar, 2012). Symptoms of cholera are characterized by acute onset of profuse watery diarrhea (described as "rice-water" stools) and frequently accompanied with vomiting. On the other hand, typhoid fever is characterized by prolonged low grade fever, intestinal dysfunction of the gut (constipation in adults, diarrhea in children), headache, a general feeling of discomfort and anorexia. Diagnosis of cholera and typhoid can be done by bacterial culture of stool and blood respectively. Serological testing may be also done to confirm cholera and typhoid fever. In case of cholera O1 or O139 antisera are measured and in case of typhoid fever Widal test can be done which estimates agglutinating antibody levels against O and H antigens. Prompt fluid replacement therapy is the core of t reatment of cholera to cure dehydration which occurs because of watery diarrhea. Antibiotics such as tetracycline, ciprofloxacin, doxycycline and co-trimoxazole may also be given to decrease the severity and duration of diarrhea In case of typhoid fever fluoroquinolones such as ofloxacin, ciprofloxacin, fleroxacin, perfloxacin are the antibiotics of choice. Rampant use of antibiotics may lead to formation of drug resistant pathogens. As both cholera and typhoid fever are waterborne and foodborne diseases, the principal measure is to ensure proper sanitation. Access to good quality and sufficient supply of water for drinking and for household chores will also prevent such diseases. Health education is crucial in making the public aware of dangers of diseases like cholera and typhoid and helping them in adapting good personal hygiene habits to prevent spread of diseases. Vaccines are also available for cholera and typhoid fever. Two types of oral cholera vaccines and a live oral vacci ne Ty2la is available for typhoid. Vi polysaccharide, a typhoid fever vaccine is also available which can be administered s.c. or i.m. Conclusion In summary, although Cholera and typhoid are similar but different, they are major public health problems, mostly in the developing world, emergence of drug resistant strains and worldwide spread due to global travel has renewed interest in these diseases. Public health awareness, better sanitation and good vaccine strategies are needed to minimize their public health impact. References Cholera.(n.d.).Retrieved from https://www.immunise. health.gov.au/internet/ immunise/publishing.nsf/Content/Handbook10-home~handbook10part4~ha Basnyat, B., Maskey, AP., Zimmerman, MD., Murdoch, DR. (2005). Enteric (typhoid) fever in travelers. Clinical Infectious Diseases, 41:1467-72. Dale, K., Kirk, M., Sinclair, M., Hall, R., L, K. (2010 ). Reported waterborne outbreaks of gastrointestinal disease in Australia are predominantly associated with recreational exposure. Aust N Z J Public Health, 527-30. Todar K, (2012). Online textbook on Bacteriology. www.textbookofbacteriology.net NNDSS Annual Report Writing Group. (2010). Australias notifiable disease status, 2008: annual report of the National Notifiable Diseases Surveillance System. Communicable Diseases Intelligence, 34:157-224. Typhoid. (n.d.). Retrieved from https://www.immunise. health.gov.au/internet/immunise/publishing.nsf/Content/Handbook10- home~handbook10part4~handbook10-4-21 World Health Organization (WHO). (2010). Cholera vaccines: WHO position paper. Weekly Epidemiological Record, 85:117-28. World Health Organization (WHO). (2008). Typhoid vaccines: WHO position paper. Weekly Epidemiological Record , 83:49-59