In a Policy Forum, Peter Hotez and colleagues discuss vaccination exemptions in US states and possible consequences for infectious disease outbreaks.

Autochthonous transmission of Trypanosoma cruzi in the United States is rarely reported. Here, we describe five newly identified patients with autochthonously acquired infections from a small pilot study of positive blood donors in southeast Texas. Case-patients 1–4 were possibly infected near their residences, which were all in the same region ∼100 miles west of Houston. Case-patient 5 was a young male with considerable exposure from routine outdoor and camping activities associated with a youth civic organization. Only one of the five autochthonous case-patients received anti-parasitic treatment. Our findings suggest an unrecognized risk of human vector-borne transmission in southeast Texas. Education of physicians and public health officials is crucial for identifying the true disease burden and source of infection in Texas.

Relapsing fever spirochetes are tick- and louse-borne pathogens that primarily afflict those in impoverished countries. Historically the pathogens have had a significant impact on public health, yet currently they are often overlooked because of the nonspecific display of disease. In this review, we discuss aspects of relapsing fever (RF) spirochete pathogenesis including the: (1) clinical manifestation of disease; (2) ability to diagnose pathogen exposure; (3) the pathogen’s life cycle in the tick and mammal; and (4) ecological factors contributing to the maintenance of RF spirochetes in nature.

Mesoamerican nephropathy (MeN), an epidemic of unexplained kidney disease in Central America, affects mostly young, healthy individuals. Its etiology is a mystery that requires urgent investigation. Largely described as a chronic kidney disease (CKD), no acute clinical scenario has been characterized. An understanding of the early disease process could elucidate an etiology and guide treatment and prevention efforts. We sought to document the earliest clinical signs in patients with suspected MeN in a high-risk population in Nicaragua. Physicians at a local hospital identified suspect cases and documented clinical/laboratory data, demographics, and medical histories. Over a 1-year period, physicians identified 255 mostly young (median 29 years), male (89.5%) patients with elevated creatinine or reduced creatinine clearance. Mean serum creatinine (2.0 ± 0.6 mg/dL) revealed a 2-fold increase from baseline, and half had stage 2 or 3 acute kidney injury. Leukocyturia (98.4%), leukocytosis (81.4%), and neutrophilia (86.2%) predominated. Nausea (59.4%), back pain (57.9%), fever (54.6%), vomiting (50.4%), headache (47.3%), and muscle weakness (45.0%) were common. A typical case of acute MeN presented with elevated (or increased ≥ 0.3 mg/dL or ≥ 1.5-fold from baseline) creatinine, no hypertension or diabetes, leukocyturia, and at least two of fever, nausea or vomiting, back pain, muscle weakness, headache, or leukocytosis and/or neutrophilia. Rapid progression (median 90 days) to CKD was recorded in 8.5% of patients. This evidence can serve as the basis of a sensitive and urgently needed case definition for disease surveillance of early-stage, acute MeN.

Protozoan pathogen Trypanosoma cruzi (Chagas, 1909) is the etiologic agent of Chagas disease, which affects millions of people in Latin America. Recently, the disease has been gaining attention in Texas and the southern United States. Transmission cycle of the parasite involves alternating infection between insect vectors and vertebrate hosts (including humans, wildlife, and domestic animals). To evaluate vector T. cruzi parasite burden and feeding patterns, we tested triatomine vectors from 23 central, southern, and northeastern counties of Texas. Out of the 68 submitted specimens, the majority were genetically identified as Triatoma gerstaeckeri (Stal, 1859), with a few samples of Triatoma sanguisuga (LeConte, 1855), Triatoma lecticularia (Stal, 1859), Triatoma rubida (Uhler, 1894), and Triatoma protracta woodi (Usinger, 1939). We found almost two-thirds of the submitted insects were polymerase chain reaction-positive for T. cruzi. Bloodmeal sources were determined for most of the insects, and 16 different species of mammals were identified as hosts. The most prevalent type of bloodmeal was human, with over half of these insects found to be positive for T. cruzi. High infection rate of the triatomine vectors combined with high incidence of feeding on humans highlight the importance of Chagas disease surveillance in Texas. With our previous findings of autochthonous transmission of Chagas disease, urgent measures are needed to increase public awareness, vector control in and around homes, and Chagas screening of residents who present with a history of a triatomine exposure.

Chagas disease (Trypanosoma cruzi infection) has recently been identified as an important neglected tropical disease in the United States. Anecdotally referred to as a “silent killer,” it leads to the development of potentially fatal cardiac disease in approximately 30% of those infected. In an attempt to better understand the potential of Chagas disease as a significant underlying cause of morbidity in Texas, we performed a historical literature review to assess disease burden. Human reports of triatomine bites and disease exposure were found to be prevalent in Texas. Despite current beliefs that Chagas disease is a recently emerging disease, we report historical references dating as far back as 1935. Both imported cases and autochthonous transmission contribute to the historical disease burden in Texas. We end by discussing the current knowledge gaps, and recommend priorities for advancing further epidemiologic studies and their policy implications.