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Severe Acute Respiratory Syndrome and Coronavirus Disease 2019

Acknowledgment The previous edition of this chapter was written by Dr. Eileen Schneider. Abstract Within the past 20 years, three novel coronaviruses have emerged from the animal kingdom to infect humans, with devastating disease and economic consequences. They were severe acute respiratory syndrome–coronavirus disease (SARS-CoV), Middle East respiratory syndrome (MERS), and SARS-CoV-2 (COVID-19). This chapter discusses SARS-CoV and introduces readers to the currently emerging SARS-CoV-2 (COVID-19).…

Ebola and Other Emerging Viral Hemorrhagic Fevers

Clinical Vignette A man in his 50s presented to a facility managing patients infected with Ebola virus disease in Guinea. He had abdominal distension, was slow to speak, and had a mildly ataxic gait. Three weeks earlier he had participated in a family funeral, and several members of that funeral party had been admitted to the unit. He denied symptoms and reported that he, being the…

Neuroangiostrongyliasis (Rat Lungworm Disease)

Abstract Neuroangiostrongyliasis (NAS), or rat lungworm disease (RLWD), is an important emerging infection spreading around the world. It is caused by Angiostrongylus cantonensis, a nematode parasite, and is the commonest parasitic cause of eosinophilic meningitis. Infection can also cause cranial nerve (CN) palsies, encephalitis, and radiculomyelitis. Another form of the disease, ocular angiostrongyliasis, is very rare but occurs when a larval worm invades the eye. Initial…

Zika Virus Disease and Congenital Zika Virus Infection

Abstract Zika virus (ZIKV) is a flavivirus primarily transmitted to humans by mosquitoes, mainly Aedes aegypti . Other commonly recognized transmission modes include sexual and intrauterine transmission. Following recognition of ZIKV transmission in Africa and Asia during the 1900s, outbreaks subsequently occurred in Pacific Island nations from 2007 and the Americas from 2015. Incidence subsequently declined, but available information suggests probable low-level ongoing transmission in parts…

Tularemia

Acknowledgment The authors would like to acknowledge Dr. Jo Hoffman who contributed to the previous edition of this chapter. Abstract Tularemia is a zoonotic bacterial infection that occurs throughout the Northern hemisphere; it is caused by several subspecies of the gram-negative coccobacillus Francisella tularensis . A wide variety of animals can be infected with F. tularensis , and the bacteria can also be carried by insects.…

Anthrax

Abstract Anthrax, caused by Bacillus anthracis, is a devastating disease for humans and animals, and one of the most important bioweapons. Though rare in the United States, natural anthrax exposure occurs sporadically worldwide. Anthrax most often manifests as cutaneous or gastrointestinal (GI) disease, with inhalation anthrax (IA) being associated with bioterrorism. Once diagnosed, anthrax must be aggressively treated with an antimicrobial regimen of fluoroquinolones, tetracycline, imipenem…

Multidrug-Resistant Tuberculosis

Abstract Tuberculosis (TB) is an important public health problem. According to the World Health Organization (WHO), approximately 10 million persons developed TB during 2018, and approximately one-fourth of the world’s population, more than 2 billion persons, are infected with Mycobacterium tuberculosis , the causative agent of TB. Worldwide, TB is the leading cause of death among persons living with human immunodeficiency virus (HIV) infection and the…

Chagas Disease

Acknowledgments The authors would like to acknowledge the work of our dear departed colleague Herbert B. Tanowitz on the previous edition chapter. Abstract Chagas disease is caused by infection with the protozoan parasite Trypanosoma cruzi. It is endemic in many areas of Latin America, where it remains an important cause of morbidity and mortality. It is a significant cause of heart disease and gastrointestinal (GI) dysfunction,…

Trichinellosis

Abstract Trichinellosis (trichinosis) is a parasitic infection caused by a roundworm of the Trichinella species. There are eight known species, and all are capable of causing human disease. The most common infections are caused by Trichinella spiralis , which can be found in pigs, rodents, horses, bears, and foxes. Another common species is Trichinella nativa , which infects humans after ingestion of infected bear or dog…

Echinococcosis: Cystic and Alveolar Disease

Abstract Within the genus Echinococcus , there are four species recognized: Echinococcus granulosus , Echinococcus multilocularis , Echinococcus vogeli , and Echinococcus oligarthrus . The larval cestodes of all four species can develop in the human host and can cause various forms of hydatid disease. A fifth species, Echinococcus shiquicus , a tapeworm of Tibetan foxes, has recently been described, but no infections have been reported…

Filarial Diseases

Abstract The filarial parasites covered in this chapter constitute a group of tissue-dwelling filarial nematodes that persist in the human host for years, causing damage to the lymphatic system that leads to elephantiasis and genital hydroceles (in the case of lymphatic filariasis) or marked inflammatory reactions in the skin and eyes leading to blindness (in the case of onchocerciasis). Both diseases are designated neglected tropical diseases…

Schistosomiasis

Abstract Schistosomiasis (bilharzia) is a disease caused by infection with parasitic flatworms known as blood flukes , belonging to the genus Schistosoma . According to the World Health Organization (WHO), schistosomiasis transmission has been reported from 78 countries, and it is estimated that more than 200 million people living in tropical endemic areas are infected. Chronic schistosomiasis causes significant morbidity and premature mortality, and negatively affects…

Food-Borne Trematodes: Liver, Lung, and Intestinal Flukes

Abstract Food-borne trematodes (FBTs) are a group of liver, lung, and intestinal flukes that typically infect humans through the ingestion of freshwater fish, crustaceans, and plants contaminated by encysted forms of the parasites. FBTs are prevalent throughout the world, with countries in Asia bearing the highest burden of infection. Transmission of FBTs is fostered by local culinary practices of consuming raw or undercooked fish and aquatic…

Cysticercosis

Abstract Cysticercosis is infection caused by the larval stage of the cestode Taenia solium , the pork tapeworm. The clinically significant helminthic invasion to central nervous system (CNS) structures and the resulting spectrum of neurologic illness define neurocysticercosis (NCC). With the more extensive use of computed tomography (CT) and magnetic resonance (MRI) neuroimaging, and the availability of accurate serologic testing, NCC has been increasingly diagnosed not…

Intestinal Cestodes (Tapeworms)

Abstract The relationship between humans and intestinal cestodes (tapeworms) goes well beyond the essential biologic interaction between host and parasite. Over time, tapeworms and tapeworm stories have contributed to human culture, literature, and dietary practices. In the late nineteenth century, part of the popular folklore was that a tapeworm infection could help make one thin, and tapeworm eggs were actually advertised commercially as a weight reduction…

Soil-Transmitted Helminths and Other Intestinal Roundworms

Abstract Infections with soil-transmitted helminths (STHs) affect the health of around 1.5 billion people around the world. Individuals of all ages may be infected with the common roundworm (Ascaris lumbricoides) , whipworm (Trichuris trichiura) , hookworm ( Ancylostoma duodenale and Necator americanus ), and Strongyloides stercoralis , although school-aged children living in resource-poor endemic areas are more likely to be infected with heavy worm burdens that…

Giardia, Cryptosporidium, Cyclospora, and Other Intestinal Protozoa

Abstract Giardia and Cryptosporidium are the two most common protozoan pathogens in the human intestine; in low-income countries, they also rank as leading causes of diarrhea in children under 5. Giardia duodenalis (previously G. lamblia or G. intestinalis ), was first discovered by Antoine van Leeuwenhoek, a 17th-century lens-grinder who invented the microscope, then found Giardia in his own stool. For the next several centuries, Giardia…

Amebiasis

Acknowledgments The authors would like to acknowledge the valuable contributions of the late Dr. Martin S. Wolfe to this chapter. Abstract Infection with Entamoeba histolytica is a leading parasitic cause of morbidity and mortality in developing nations and is an important health risk to travelers. Amebiasis is transmitted by parasite cysts via fecal-oral contamination from infected individuals or from contaminated food or water. Although most infected…