American Journal of Tropical Medicine and Hygiene最新文献

In the present study, a tiled amplification protocol was developed to cover the three segments of Choclo virus (CHOV), which was subsequently used for sequencing samples from different provinces within the endemic zone in Panama. The developed protocol yielded a coverage of the CHOV genome greater than 99% for most of the sample's segments, and the four consensus sequences obtained had a mean coverage of 94-99%. Generating a significant number of whole-genome sequences is necessary for studying genomic characteristics among CHOV isolated from rodent hosts, as well as those isolated from human samples. Employing enhanced methodology for whole-genome consensus facilitates the validation and advancement of cutting-edge detection methods, while also providing valuable insights for comprehensive studies on CHOV.

Malaria caused mass casualties among US military personnel during the Vietnam War, resulting in as many hospitalizations as combat wounds in 1965. Its military impact was magnified because nearly all the disease-related casualties came from front-line units, particularly the infantry, with rates exceeding 10 per 1,000 man-days of exposure. The imperfect chemoprophylaxis using chloroquine-primaquine tablets developed during the Korean War proved inadequate. Adding daily dapsone was more effective but resulted in rare cases of agranulocytosis and at least eight deaths. After Vietnam, malaria in US military members, especially relapsing malaria due to Plasmodium vivax, caused thousands of infections in the United States, although indigenous transmission was rarely observed. Although severe malaria resulted in 78 known deaths in the US Army (and 46 in the US Marines), the real military issue was lost days due to illness, averaging more than 1 month per malaria case and at least 200,000 lost man-days per year. Malaria's potential to produce mass casualties in soldiers remains, especially during deployments to New Guinea or sub-Saharan Africa.

Dengue is the most widespread mosquito-borne viral disease globally, as well as in India. Children are most susceptible to acquiring severe primary dengue infection because the protective levels of maternal antibodies decline over time. In view of the forthcoming introduction of dengue vaccines, understanding the kinetics of maternal antibodies is a critical parameter for determining the correct age of immunization in children. In this cross-sectional study conducted at a tertiary care hospital in Pune, India, 602 serum samples from infants were screened for anti-dengue IgG antibodies using ELISA. Dengue-specific antibodies were found in 71% of cord blood samples and gradually declined to 63%, 14%, 3%, 5%, and 7% in infants by the ages of 3, 6, 9, 12, and 15 months, respectively. At 3 months of age, 14 of 72 (19%) infants acquired dengue infection and became seropositive for anti-dengue IgM antibodies. A total of 80% (36/45) of infants tested for neutralizing antibodies at birth were positive for three or four dengue virus (DENV) serotypes. Geometric mean titers of neutralizing antibodies decreased to the lowest levels of 87%, 98%, 88%, and 92% against DENV-1, DENV-2, DENV-3, and DENV-4 in 9-month-old infants. The study results suggest that maternal antibodies drastically reduced in infants by the age of 6 months, and infants as young as 3 months were susceptible to dengue infection. In summary, the data in the current study provide useful insights into the kinetics of maternally transferred antibodies and susceptibility of Indian infants to DENV.

The diagnosis and treatment of schistosomiasis among migrants in nonendemic countries are still challenging. An online questionnaire was sent to adult and pediatric infectious disease specialists through the French infectious disease societies' mailing lists to assess attitudes and practices toward the disease. We included all individuals who responded to the online questionnaire but excluded from analysis residents and doctors with dual practices (adults and children) from the analysis. The questionnaire consisted of 19 questions about professional status, screening practices, diagnostic methods, treatment protocols, and follow-up. The response rate was 10.5% (n = 102/970); four respondents were excluded, including two medical residents and two respondents with dual practices. Adult and pediatric infectious disease specialists participated in the study. Serology was the most frequently used diagnostic method among asymptomatic patients. The preferred imaging examination was ultrasound, especially among pediatricians. Praziquantel treatment dose schemes were heterogeneous; 55 of 98 respondents prescribed more than one dose. Serology was still used by 23% (n = 23/98) of the respondents as a follow-up tool despite its irrelevance. The management of chronic schistosomiasis in nonendemic countries is heterogeneous even among infectious disease specialists. New guidelines need to consider the diversity of nosological frameworks.

Haemaphysalis leporispalustris (the rabbit tick) is one of the most broadly distributed hard tick species in the Americas. In 2018, investigators amplified DNA from a spotted fever group Rickettsia (SFGR) species found in host-seeking larvae and nymphs of H. leporispalustris collected in northern California and proposed the name Candidatus "Rickettsia lanei" using results obtained via multilocus sequence typing. Several years later, other investigators reported the amplification of DNA from the blood of two severely ill patients in northern California that demonstrated near-identical sequences with several gene sequences of Ca. "R. lanei," suggesting that this SFGR is pathogenic to humans. Recently, nearly complete genetic identity was identified between segments of the outer membrane protein A gene of Ca. "R. lanei" and an otherwise unidentified SFGR isolate designated as HLP 7421, which was established in 1961 from H. leporispalustris collected in the Bitterroot Valley of western Montana. Herein, the results of whole-genome sequencing of HLP 7421 are reported, revealing a 1,270,740 base pair chromosome most similar to that of Rickettsia rickettsii subsp. californica, the etiologic agent of Pacific Coast tick fever. Digital DNA-DNA hybridization and orthologous average nucleotide identity percentages between HLP 7421 and several closely related SFGR species meet the criteria for species identification using one genome-based algorithm for defining taxa in the Rickettsia genus. The name Rickettsia lanei is proposed for this pathogen, and its potential contribution to the evolving mosaic of tick-borne spotted fevers in the Americas is discussed.

Onchocerciasis is a neglected tropical disease that has severe health and socioeconomic impacts on the mostly poor and underserved communities in disease-endemic areas. Despite significant global progress toward the elimination of onchocerciasis transmission there remains a high risk of reemergence in areas where the disease was previously eliminated. Here we discuss the potential risk factors for the reemergence of onchocerciasis in disease-free zones in Sudan and nearby countries resulting from war-induced massive population displacement. We urge public health, humanitarian, and development stakeholders to invest in policymaking, strategic planning, resource mobilization, and development and implementation of sustainable and cost-effective prevention and control interventions for onchocerciasis, particularly among the most vulnerable high-risk populations.