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Neuroinfectious Diseases
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
Jeremy D. Young, Jesica A. Herrick, Scott Borgetti
C. neoformans is a ubiquitous environmental saprophyte, found in soil and decaying vegetation worldwide. These yeasts thrive in the GI tract of some birds, such as pigeons and chickens, and are often found near bird roosts. Organisms do not cause disease in these intermediate hosts, but can become infectious to humans when inhaled.
The Host Immune Response Against Parasitic Helminth Infection
Published in Peter D. Walzer, Robert M. Genta, Parasitic Infections in the Compromised Host, 2020
Parasitic helminths have evolved mechanisms for avoiding rejection by the immune system in their evolutionary adaptation to life within the human host. Because these parasites must survive within the definitive host for a period of time that is sufficiently long to ensure continued transmission of the infective stages to their intermediate hosts, it is not suprprising that chronic infections are required to maintain the life cycle.
Host Defense II: Acquired Immunity
Published in Constantin A. Bona, Francisco A. Bonilla, Textbook of Immunology, 2019
Constantin A. Bona, Francisco A. Bonilla
Schistosome infestation is one of the most prevalent infectious illnesses in tropical regions, with an estimated 200 million people affected worldwide (3.6 percent of the total human population). The intermediate hosts for schistosomes are aquatic or amphibious snails. The schistosome life cycle is illustrated in Figure 11–4.
Cerebral toxoplasmosis in HIV-infected patients: a review
Published in Pathogens and Global Health, 2023
Sofiati Dian, Ahmad Rizal Ganiem, Savira Ekawardhani
A non-sporulated oocyst excreted in cat feces transforms into a highly infectious sporulated form in fresh air [17,18]. The sexual reproductive phase of T. gondii occurs only in cats, its definitive host, facilitated by the intrinsic abundance of linoleic acid and the absence of the enzyme delta-6-desaturase. The intermediate host, including humans, mammals, and birds are infected after consuming water or food contaminated by infectious oocyst or after ingesting prey containing tissue cysts [18]. The cyst wall is later digested in the host’s stomach and intestine, releasing bradyzoites, which penetrate further into the epithelium of the intestine. Inside the cysts, several hundred bradyzoites remain covered from the host immune system. Host immune responses and anti-toxoplasmosis can limit their growth and force the tachyzoite to transform into slowly replicating bradyzoites. Bradyzoites become active when the immune system becomes compromised, leading to clinical manifestation [18].
Vaccine for a neglected tropical disease Taenia solium cysticercosis: fight for eradication against all odds
Published in Expert Review of Vaccines, 2021
Rimanpreet Kaur, Naina Arora, Suraj S Rawat, Anand Kumar Keshri, Shubha Rani Sharma, Amit Mishra, Gagandeep Singh, Amit Prasad
Although there are several studies about how to identify an infected pig based on clinical signs, by tongue examination of pig or by serology are available, these are not going to deter the pork seller from selling the infected pork in the absence of stringent implementation of related laws in poor endemic areas [19,20,23–32]. Immunizing the host (definite or intermediate) of the infectious disease is considered the most successful way to control most of the vector-borne infectious diseases and in the case of Taenia, targeting an intermediate host (pig) is considered to be a better option than human due to several reasons as outlined above. Pig vaccination provides an alternative approach for reducing the exposure of humans to infectious meat sources, which will lead to reduced incidence of taeniasis that will lead to less cysticercosis eventually. Animal vaccination is considered less expensive and easy to implement too when compared to human vaccination. Hence, many attempts have been made to make an effective vaccine for pigs. This corroborates the need for a swine vaccine and its use as a much-required tool for the fight against cysticercosis.
Tick transmission of toxoplasmosis
Published in Expert Review of Anti-infective Therapy, 2019
Toxoplasmosis is thought to be acquired by the transmission of T. gondii from the definitive to intermediate hosts, from intermediate to definitive hosts, as well as between similar definitive and between similar intermediate hosts. Intermediate hosts are all warm-blooded animals (mammals and birds), including humans. Definitive hosts are members of the family Felidae, for example, domestic cats [2]. Humans most commonly acquire toxoplasmosis by ingestion of T. gondii cysts in infected meat or by the ingestion of sporulated oocysts from water, soil or food contaminated indirectly from feline feces, or less frequently, directly from feline feces [2,9]. In the US, T. gondii is second only to Salmonella as a domestically acquired foodborne illness resulting in death [10]. Transmission by blood transfusion [11] and organ transplantation [12] has also been reported. Little is known about the relative importance of horizontal transmission of T. gondii between different host species or the epidemiologic impact of the different sources causing infection or disease.