Molecular characterization and zoonotic potential of Cryptosporidium in free-ranging poultry in rural Madagascar Public

Schwaner, Caroline Lowe (2014)

Permanent URL: https://etd.library.emory.edu/concern/etds/8g84mm78b?locale=fr
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Abstract

Zoonotic pathogens are a major global health concern. With increasing deforestation and human encroachment, zoonotic pathogens have begun to pose a serious threat to human health and overall ecosystem health. Despite the preliminary understanding of zoonosis, much is left to learn about the ecology, epidemiology, and transmission of these infectious diseases. On the island of Madagascar, diarrheal disease is a major public health burden and the leading cause of death for children under five years of age. Cryptosporidium is a protozoan parasite that can infect the majority of mammals and birds. Previous studies have examined the zoonotic potential of Cryptosporidium in mammals in rural developing landscapes, but the role of poultry has not been fully examined. To investigate poultry's role in the transmission of Cryptosporidium, from May to August 2012, fecal samples were collected from chickens, ducks, and geese in southeastern Madagascar. DNA was extracted from the samples using 18S PCR of the SSU rRNA gene and species of Cryptosporidium were defined using Restriction Fragment Length Polymorphism (RFLP). There was a presence of Cryptosporidium in these three villages in humans, livestock, poultry, and rodents. Poultry had the highest percentage of infection. RFLP evidence suggests that species of Cryptosporidium were found in their expected species, with some suspect results. It appears that poultry do not represent a source of zoonotic Cryptosporidium for humans in this region of Madagascar. These findings highlight that although Cryptosporidium is prevalent in poultry in this rural system, the species of Cryptosporidium occurring in poultry and humans in this system are distinct.

Table of Contents

Table of Contents

Table of Contents Page Abstract.......................................................................................................................... 1 Introduction...................................................................................................................

Madagascar and Diarrheal Diseases

Cryptosporidium

Disease Risk of Poultry

2 3 5 5 Objectives/Hypothesis................................................................................................... 7

Methods.......................................................................................................................... Fecal Sample Collection.................................................................................................. DNA Extraction................................................................................................................

18s Polymerase Chain Reaction......................................................................................

Restriction Fragment Length Polymorphism .................................................................. Statistical Analysis........................................................................................................... Ethical Considerations.....................................................................................................

9 9 10 10 11 11 12 Results............................................................................................................................ 13 Discussion........................................................................................................................ 16 References....................................................................................................................... 26 Tables.............................................................................................................................. 31 Figures............................................................................................................................ 35 List of Tables Page

Table 1. Presence of Cryptosporidium in fecal samples from poultry, livestock, humans and rodents in rural villages in Ifanadiana district, Madagascar........................

31

Table 2. Presence of Cryptosporidium in poultry, livestock, rodents, and humans at the village level in Ambatolahy, Ambodiaviavy, and Ankialo in rural Madagascar......

31

Table 3. Different species of livestock, rodents, and poultry sampled from the same households of Ambodiaviavy, Ankialo, and Ambatolahy, Madagascar.......................

32

Table 4. Total Presence of Cryptosporidium in poultry and humans in rural villages of Ifanadiana district, Madagascar ................................................................................

33

Table 5. Logistic Regression Analysis of Cryptosporidium presence and poultry, villages, and the interaction between species and villages in samples from Ambatolahy, Ambodiaviavy, and Ankialo in rural Madagasarcar..................................

33

Table 6. Description of poultry fecal samples found to be positive for Cryptosporidium collected in Ambodiaviavy, Ankialo, and Ambatolahy, Madagascar during the 2012 field season............................................................................................

34 List of Figures Page

Figure 1. The transmission and interactions of poultry within and between villages and with urban centers or other fowls(modified from Kitalyi, 1998)............................

35

Figure 2. Map of the 2012 field study sights (Ankialo, Ambatolahy, and Ambodiaviavy) in the Ifnadiana District in Southeastern Madagascar (Modified from Brian Gerber)...................................................................................................................

36

Figure 3. Interpreting bands on UV image after gel electrophoresis to determine whether samples were positive for Cryptosporidium......................................................

37

Figure 4-7. Restriction Fragment Length Polymporphism (RFLP) species level identification of Cryptosporidium using SSpI.................................................................

38

Figure 8 & 9 . Restriction Fragment Length Polymorphism species level Identification of Cryptosporidium using VspI.................................................................

38

Figure 10. Restriction Fragment Length Polymorphism results demonstrating that rodent samples had the expected species C. muris..........................................................

39

Figure 11. Potential route of zoonotic transmission of Cryptosporidium between humans and poultry, based on observed interactions of poultry, humans, and water sources in rural villages in southeastern Madagascar......................................................

40

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