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Global distribution, public health and clinical impact of the protozoan pathogen cryptosporidium.

Putignani L, Menichella D - Interdiscip Perspect Infect Dis (2010)

Bottom Line: Principal key indicators of the parasite distribution were associated to environmental (e.g., geographic and temporal clusters, etc.) and host determinants of the infection (e.g., age, immunological status, travels, community behaviours).The distribution was geographically mapped to provide an updated picture of the global parasite ecosystems.The present paper aims to provide, by a critical analysis of existing literature, a link between observational epidemiological records and new insights on public health, and diagnostic and clinical impact of cryptosporidiosis.

View Article: PubMed Central - PubMed

Affiliation: Microbiology Unit, Bambino Gesù Pediatric Hospital, Scientific Institute, Piazza Sant'Onofrio 4, 00165 Rome, Italy.

ABSTRACT
Cryptosporidium spp. are coccidians, oocysts-forming apicomplexan protozoa, which complete their life cycle both in humans and animals, through zoonotic and anthroponotic transmission, causing cryptosporidiosis. The global burden of this disease is still underascertained, due to a conundrum transmission modality, only partially unveiled, and on a plethora of detection systems still inadequate or only partially applied for worldwide surveillance. In children, cryptosporidiosis encumber is even less recorded and often misidentified due to physiological reasons such as early-age unpaired immunological response. Furthermore, malnutrition in underdeveloped countries or clinical underestimation of protozoan etiology in developed countries contribute to the underestimation of the worldwide burden. Principal key indicators of the parasite distribution were associated to environmental (e.g., geographic and temporal clusters, etc.) and host determinants of the infection (e.g., age, immunological status, travels, community behaviours). The distribution was geographically mapped to provide an updated picture of the global parasite ecosystems. The present paper aims to provide, by a critical analysis of existing literature, a link between observational epidemiological records and new insights on public health, and diagnostic and clinical impact of cryptosporidiosis.

No MeSH data available.


Related in: MedlinePlus

Description of transmission modes of Cryptosporidium. Following ingestion (and possibly inhalation) by a suitable host (e.g., human host), excystation occurs (infective stage, (1)). The released sporozoites invade epithelial cells of the gastrointestinal tract or other tissues, complete their cycle producing oocysts which exit host (diagnostic stage, (2)) and are released in the environment (3). Transmission of Cryptosporidium mainly occurs by ingestion of contaminated water (e.g., surface, drinking or recreational water), food sources (e.g., chicken salad, fruits, vegetables) or by person-to-person contact (community and hospital infections) (4). Zoonotic transmission of C. parvum occurs through exposure to infected animals (person-to-animal contact) or exposure to water (reservoir) contaminated by feces of infected animals (4). Putignani and Menchella, 2010.
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Related In: Results  -  Collection


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fig2: Description of transmission modes of Cryptosporidium. Following ingestion (and possibly inhalation) by a suitable host (e.g., human host), excystation occurs (infective stage, (1)). The released sporozoites invade epithelial cells of the gastrointestinal tract or other tissues, complete their cycle producing oocysts which exit host (diagnostic stage, (2)) and are released in the environment (3). Transmission of Cryptosporidium mainly occurs by ingestion of contaminated water (e.g., surface, drinking or recreational water), food sources (e.g., chicken salad, fruits, vegetables) or by person-to-person contact (community and hospital infections) (4). Zoonotic transmission of C. parvum occurs through exposure to infected animals (person-to-animal contact) or exposure to water (reservoir) contaminated by feces of infected animals (4). Putignani and Menchella, 2010.

Mentions: Infections of the human gastrointestinal tract with enteric pathogens are among the leading causes of disease, suffering, and death worldwide. Enteric pathogens are ingested with contaminated water and food and pass through the entire gastrointestinal tract. After establishment in a host, the infection spread to new hosts by a subsequent shedding. The most important and prevalent infections of the small intestine are caused by diarrheagenic Escherichia coli, particularly enterotoxigenic and enteropathogenic E. coli, Rotavirus, Giardia lamblia, and Cryptosporidium parvum [1–3]. Particularly, more than 58 million cases of diarrhea detected per year in children are associated to intestinal protozoa infections with high morbidity and mortality infection rates [4]. Cryptosporidium spp. are oocysts-forming apicomplexan protozoa. Following ingestion, the oocyst excystation, releases sporozoites which invade enterocytes. The excysted parasites undergo asexual (merogony) and sexual multiplication (gametogony) producing macrogametocytes and microgametocytes. Upon fertilization of the macrogametocytes by microgametes a zygotes is developed which sporulates (sporogony), generating thin-walled oocysts, involved in autoinfection and thick-walled oocysts excreted from the host (Figure 1). Once released in the environment, the parasite may cause enteric infection (cryptosporidiosis) both in humans and animals, mainly transmitted via the fecal-oral route through a zoonotic or anthroponotic modality or via contaminated water or food (Figure 2). In humans the disease results in sickness and severe diarrhea and can be life threatening in the very young, elderly and in immunosuppressed individuals, particularly those with HIV infection [5]. Contamination of drinking water by Cryptosporidium can result in major waterborne outbreaks of cryptosporidiosis [6]; additionally the Cryptosporidium is now increasingly considered an important foodborne pathogen [7, 8] causing a disease of socioeconomic significance worldwide. Three features of Cryptosporidium spp. ensure a high level of environmental contamination and increase the likelihood of waterborne transmission. Firstly, they are responsible for disease in a broad range of hosts including man [9, 10], have a low-infectious dose (10–30 oocysts) enhancing the possibility of infection also in healthy immunocompetent people [11, 12], which may shed 108-109 oocysts in a single bowel movement and excrete oocysts for up to 50 days after cessation of diarrhea [13, 14]; secondly, their transmissive stages (oocysts) are small in size and environmentally robust [15, 16] and thirdly, they are insensitive to the normal disinfectants commonly used in the water industry [17, 18].


Global distribution, public health and clinical impact of the protozoan pathogen cryptosporidium.

Putignani L, Menichella D - Interdiscip Perspect Infect Dis (2010)

Description of transmission modes of Cryptosporidium. Following ingestion (and possibly inhalation) by a suitable host (e.g., human host), excystation occurs (infective stage, (1)). The released sporozoites invade epithelial cells of the gastrointestinal tract or other tissues, complete their cycle producing oocysts which exit host (diagnostic stage, (2)) and are released in the environment (3). Transmission of Cryptosporidium mainly occurs by ingestion of contaminated water (e.g., surface, drinking or recreational water), food sources (e.g., chicken salad, fruits, vegetables) or by person-to-person contact (community and hospital infections) (4). Zoonotic transmission of C. parvum occurs through exposure to infected animals (person-to-animal contact) or exposure to water (reservoir) contaminated by feces of infected animals (4). Putignani and Menchella, 2010.
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig2: Description of transmission modes of Cryptosporidium. Following ingestion (and possibly inhalation) by a suitable host (e.g., human host), excystation occurs (infective stage, (1)). The released sporozoites invade epithelial cells of the gastrointestinal tract or other tissues, complete their cycle producing oocysts which exit host (diagnostic stage, (2)) and are released in the environment (3). Transmission of Cryptosporidium mainly occurs by ingestion of contaminated water (e.g., surface, drinking or recreational water), food sources (e.g., chicken salad, fruits, vegetables) or by person-to-person contact (community and hospital infections) (4). Zoonotic transmission of C. parvum occurs through exposure to infected animals (person-to-animal contact) or exposure to water (reservoir) contaminated by feces of infected animals (4). Putignani and Menchella, 2010.
Mentions: Infections of the human gastrointestinal tract with enteric pathogens are among the leading causes of disease, suffering, and death worldwide. Enteric pathogens are ingested with contaminated water and food and pass through the entire gastrointestinal tract. After establishment in a host, the infection spread to new hosts by a subsequent shedding. The most important and prevalent infections of the small intestine are caused by diarrheagenic Escherichia coli, particularly enterotoxigenic and enteropathogenic E. coli, Rotavirus, Giardia lamblia, and Cryptosporidium parvum [1–3]. Particularly, more than 58 million cases of diarrhea detected per year in children are associated to intestinal protozoa infections with high morbidity and mortality infection rates [4]. Cryptosporidium spp. are oocysts-forming apicomplexan protozoa. Following ingestion, the oocyst excystation, releases sporozoites which invade enterocytes. The excysted parasites undergo asexual (merogony) and sexual multiplication (gametogony) producing macrogametocytes and microgametocytes. Upon fertilization of the macrogametocytes by microgametes a zygotes is developed which sporulates (sporogony), generating thin-walled oocysts, involved in autoinfection and thick-walled oocysts excreted from the host (Figure 1). Once released in the environment, the parasite may cause enteric infection (cryptosporidiosis) both in humans and animals, mainly transmitted via the fecal-oral route through a zoonotic or anthroponotic modality or via contaminated water or food (Figure 2). In humans the disease results in sickness and severe diarrhea and can be life threatening in the very young, elderly and in immunosuppressed individuals, particularly those with HIV infection [5]. Contamination of drinking water by Cryptosporidium can result in major waterborne outbreaks of cryptosporidiosis [6]; additionally the Cryptosporidium is now increasingly considered an important foodborne pathogen [7, 8] causing a disease of socioeconomic significance worldwide. Three features of Cryptosporidium spp. ensure a high level of environmental contamination and increase the likelihood of waterborne transmission. Firstly, they are responsible for disease in a broad range of hosts including man [9, 10], have a low-infectious dose (10–30 oocysts) enhancing the possibility of infection also in healthy immunocompetent people [11, 12], which may shed 108-109 oocysts in a single bowel movement and excrete oocysts for up to 50 days after cessation of diarrhea [13, 14]; secondly, their transmissive stages (oocysts) are small in size and environmentally robust [15, 16] and thirdly, they are insensitive to the normal disinfectants commonly used in the water industry [17, 18].

Bottom Line: Principal key indicators of the parasite distribution were associated to environmental (e.g., geographic and temporal clusters, etc.) and host determinants of the infection (e.g., age, immunological status, travels, community behaviours).The distribution was geographically mapped to provide an updated picture of the global parasite ecosystems.The present paper aims to provide, by a critical analysis of existing literature, a link between observational epidemiological records and new insights on public health, and diagnostic and clinical impact of cryptosporidiosis.

View Article: PubMed Central - PubMed

Affiliation: Microbiology Unit, Bambino Gesù Pediatric Hospital, Scientific Institute, Piazza Sant'Onofrio 4, 00165 Rome, Italy.

ABSTRACT
Cryptosporidium spp. are coccidians, oocysts-forming apicomplexan protozoa, which complete their life cycle both in humans and animals, through zoonotic and anthroponotic transmission, causing cryptosporidiosis. The global burden of this disease is still underascertained, due to a conundrum transmission modality, only partially unveiled, and on a plethora of detection systems still inadequate or only partially applied for worldwide surveillance. In children, cryptosporidiosis encumber is even less recorded and often misidentified due to physiological reasons such as early-age unpaired immunological response. Furthermore, malnutrition in underdeveloped countries or clinical underestimation of protozoan etiology in developed countries contribute to the underestimation of the worldwide burden. Principal key indicators of the parasite distribution were associated to environmental (e.g., geographic and temporal clusters, etc.) and host determinants of the infection (e.g., age, immunological status, travels, community behaviours). The distribution was geographically mapped to provide an updated picture of the global parasite ecosystems. The present paper aims to provide, by a critical analysis of existing literature, a link between observational epidemiological records and new insights on public health, and diagnostic and clinical impact of cryptosporidiosis.

No MeSH data available.


Related in: MedlinePlus