Chagas Disease Chagas disease, an infection caused by the protozoan parasite T cruzi, is seen in Mexico and central and South America The parasite is transmitted through feces of infected triatomine insects (kissing bugs) after a blood meal The global prevalence is to 10 million The common initial presentation is a painless red nodule known as a chagoma that develops at the site of initial inoculation Most develop low-grade fever, generalized lymphadenopathy, and malaise Rare acute presentations include myocarditis, hepatosplenomegaly, edema, and meningoencephalitis While most cases resolve over to months, in approximately 20% of patients, serious sequelae such as dilated cardiomyopathy, megaesophagus, and megacolon may occur years to decades after the initial infection Cardiac manifestations include pericardial effusion which can lead to tamponade physiology, left ventricular aneurysms, abnormal diastolic function, contractile anomalies, and characteristic EKG findings (right bundle branch block, left anterior block, AV block, sinus bradycardia, and ST segment, T- and Q-wave abnormalities) Mortality is due to ventricular arrhythmias, complete heart block, congestive heart failure, or emboli Diagnosis is made via Giemsa staining of blood specimens or by direct wet mount prep Serologies, available via the CDC, are used to diagnose chronic Chagas Treatment is with antitrypanosomal medications such as benznidazole (for 30 to 90 days) or nifurtimox (for 90 to 120 days) The latter can be obtained from the CDC under a compassionate use protocol: (404) 718-4745 Expert consultation is strongly recommended Travelers should avoid contact with the triatomine bug by utilizing insecticide and bed netting and avoiding habitation in buildings constructed of mud, palm thatch, or adobe brick Standard precautions are recommended RESPIRATORY TRACT INFECTIONS The most common respiratory infections in returned travelers will be simple viral infections However, knowledge of the region of travel can alert clinicians to either common viruses with different seasonality in other hemispheres (e.g., influenza virus in the middle of the calendar year in subequatorial nations) or for pathogens more common in other settings The latter includes tuberculosis (described earlier in the chapter), some vaccine-preventable diseases more common in developing nations (e.g., diphtheria), and emerging infections, such as the coronaviruses causing Severe Acute Respiratory Syndrome (SARS) and Middle Eastern Respiratory Syndrome (MERS), which were first reported in Asia and the Middle East, respectively Coronaviruses (SARS, MERS) Coronaviruses are common causes of mild upper respiratory tract infections, and are known to cause lower respiratory tract disease, primarily in young or immunocompromised children In 2002, SARS caused a febrile illness associated with ARDS and a mortality rate that exceeded 50% in older adults Disease severity was milder in young children Laboratory findings included leukopenia, elevated LDH, and elevated creatinine kinase In 2012, MERS was first described in a Saudi Arabian man who died of ARDS Symptoms include fever, chills, myalgias, and a minority of patients develop diarrhea Acute kidney injury and multiorgan failure can be seen Treatment is supportive Contact and droplet precautions should be used Diphtheria Diphtheria, a bacterial infection caused by an exotoxin-producing gram-positive bacillus, Corynebacterium diphtheriae, remains an important disease in resource-poor countries and has experienced resurgence in recent years in Russia, Haiti, and other countries Diphtheria is spread via contact with respiratory secretions (airborne, droplet, or direct contact) or skin lesions Infection may lead to an asymptomatic carrier state, respiratory disease, or cutaneous disease Faucial (nasopharyngeal) diphtheria is the most common form of the disease and is characterized by the gradual onset of a moderate fever, malaise, and pharyngitis in 80% with a gray-white pseudomembrane usually covering one or both tonsils A characteristic odor is usually present Extensive membranous pharyngitis may ensue, causing significant swelling of the tonsils, uvula, anterior neck, and regional lymph nodes causing a “bull neck” appearance Stridor can be seen with laryngeal involvement Fever, if present at all, usually is low grade Severe complications are seen in approximately 10% of patients and include myocarditis with arrhythmias or heart failure, or neuritis of the palatal, bulbar, or skeletal muscles Baseline EKGs should be obtained in a patient with suspected diphtheria Cutaneous diphtheria is now more common than nasopharyngeal disease in the West, with recent resurgence seen in homeless persons in the United States Chronic, painless nonhealing scaly rashes with well-demarcated borders or ulcers with a gray membrane appearance characterize skin involvement