The American Journal of Tropical Medicine and Hygiene - Current Issue

This article describes similarities and differences in the response of governments and the international community to the current 2019 coronavirus disease (COVID-19) and the 2014 West African Ebola epidemic. It expresses the opinion that the speed and scale of the response to COVID-19 are affected by the important role that China plays in the global economy. By contrast, insufficient and less timely action was initially undertaken in West African countries during the 2014 Ebola epidemic. It concludes by stating why preparedness for and response to all disease outbreaks, also in countries of lower economic importance, should become a priority in the global health agenda.

The optimal time to initiate research on emergencies is before they occur. However, timely initiation of high-quality research may launch during an emergency under the right conditions. These include an appropriate context, clarity in scientific aims, preexisting resources, strong operational and research structures that are facile, and good governance. Here, Nebraskan rapid research efforts early during the 2020 coronavirus disease pandemic, while participating in the first use of U.S. federal quarantine in 50 years, are described from these aspects, as the global experience with this severe emerging infection grew apace. The experience has lessons in purpose, structure, function, and performance of research in any emergency, when facing any threat.

Malaria clinical studies entailing the experimental infection of healthy volunteers with Plasmodium parasites by bites from infected mosquitos, injection of cryopreserved sporozoites, or injection of blood-stage parasites provide valuable information for vaccine and drug development. Success of these studies depends on maintaining safety. In this mini-review, we discuss the safety risks and associated mitigation strategies of these three types of experimental malaria infection. We aimed to inform researchers and regulators who are currently involved in or are planning to establish experimental malaria infection studies in endemic or non-endemic settings.

This case report underlines the appearance of a “walking pneumonia” in a novel coronavirus disease (COVID-19) patient, with evidence of progressive lung involvement on chest imaging studies. The patient traveled from Wuhan, Hubei, China, to Thailand in January 2020. One of her family members was diagnosed with COVID-19. She presented to the hospital because of her concern, but she was without fever or any respiratory symptoms. Three days earlier, her nasopharyngeal and throat swabs revealed a negative severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) test by real-time reverse transcriptase polymerase chain reaction (RT-PCR). Her initial chest radiography was abnormal, and her first sputum SARS-CoV-2 test yielded inconclusive results. A subsequent sputum test was positive for SARS-CoV-2. Diagnosis in this patient was facilitated by chest imaging and repeat viral testing. Thus, chest imaging studies might enhance capabilities for early diagnosis of COVID-19 pneumonia.

Dengue is the most common mosquito-borne flaviviral infection in the world today. Several factors contribute and act synergistically to cause severe infection. One of these is dysregulated host immunological mediators that cause transient pathophysiology during infection. These mediators act on the endothelium to increase vascular permeability, which leads to plasma leakage compromising hemodynamics and coagulopathy. We conducted a prospective study to explore the expression of pro- and anti-inflammatory cytokines and how they relate to clinical dengue manifestations, by assessing their dynamics through acute dengue infection in adults admitted to the Hospital for Tropical Diseases, Bangkok, Thailand. We performed cytokine analysis at three phases of infection for 96 hospitalized adults together with serotyping of confirmed dengue infection during the outbreaks of 2015 and 2016. The serum concentrations of seven cytokines (interleukin [IL]-2, IL-4, IL-6, IL-8, IL-10, tumor necrosis factor alpha, and interferon gamma) were measured in duplicate using a commercial kit (Bio-Plex Human Cytokine Assay). In this study, the cytokine profile was suggestive of a T-helper 2 response. Most patients had secondary infection, and the levels of viremia were higher in patients with plasma leakage than those without plasma leakage. In addition, we observed that bleeding and hepatitis were associated with significantly higher levels of IL-8 during the early phases of infection. Furthermore, IL-6 levels in the early phase of infection were also elevated in bleeding patients with plasma leakage. These results suggest that IL-6 and IL-8 may act in synergy to cause bleeding in patients with plasma leakage.

Four formulations of an investigational tetravalent dengue purified inactivated vaccine, administered as two doses one month (M) apart, were previously shown to be immunogenic and well-tolerated up to M13 of the phase I study NCT01702857. Here, we report results of the follow-up from M14 to year (Y) 3. One hundred healthy Puerto Rican adults, predominantly dengue virus (DENV)–primed, were randomized 1:1:1:1:1 to receive placebo or vaccine formulations: 1 μg/serotype/dose adjuvanted with aluminum, AS01E or AS03B, or aluminum-adjuvanted 4 μg/serotype/dose. No serious adverse events occurred. Two medically-attended potential immune-mediated disease cases, vaccination unrelated, were reported (groups 1 µg+Alum and 1 µg+AS03B). Of 14 instances of suspected dengue, none were laboratory confirmed. Geometric mean neutralizing antibody titers against DENV 1-4 waned from M14, but remained above pre-vaccination levels for DENV 1-3, with the highest values for group 1 µg+AS03B: 1220.1, 920.5, 819.4, and 940.5 (Y2), and 1329.3, 1169.2, 1219.8, and 718.9 (Y3). All formulations appeared to be safe and immunogenic during the 3-year follow-up.

Following the large outbreak of Zika virus in the Western Hemisphere, many infants have been born with congenital Zika virus infection. It is important to describe the functional outcomes seen with congenital infections to allow for their recognition and appropriate interventions. We evaluated 120 children conceived during the 2015–2016 Zika virus outbreak in Paraíba, Brazil, who were approximately 24 months old, to assess functional outcomes. All children met either anthropometric criteria or laboratory criteria suggestive of possible congenital Zika virus infection. We collected results of previous medical evaluations, interviewed parents, and performed physical examinations and functional assessments, for example, the Hammersmith Infant Neurological Examination (HINE). We compared patterns of neurologic outcomes and developmental delay at age 24 months by whether children met anthropometric or laboratory criteria, or both. Among children meeting both criteria, 60% (26/43) were multiply affected (had severe motor impairment, severe developmental delay, and suboptimal HINE scores), compared with 5% (3/57) meeting only laboratory criteria and none (0/20) meeting only anthropometric criteria. Of the remaining 91 children, 49% (45) had developmental delay, with more severe delay seen in children meeting both criteria. Although children meeting physical and laboratory criteria for potential congenital Zika virus infection were more severely affected, we did identify several children with notable adverse neurologic outcomes and developmental delay with no physical findings but potential laboratory evidence of Zika virus infection. Given this, all children who were potentially exposed in utero to Zika virus should be monitored in early childhood for deficits to allow for early intervention.

Two confirmed human cases of Zika virus (ZIKV) were reported in the district of Miri, Sarawak, in 2016. Following that, a mosquito-based ZIKV surveillance study was conducted within 200-m radius from the case houses. Mosquito surveillance was conducted using five different methods, that is, biogents sentinel mosquito (BG) sentinel trap, modified sticky ovitrap, resting catch, larval surveillance, and conventional ovitrap. A total of 527 and 390 mosquito samples were obtained from the case houses in two localities, namely, Kampung Lopeng and Taman Shang Ri La, Miri, Sarawak, respectively. All mosquitoes collected were identified, which consisted of 11 species. Aedes albopictus, both the adult and larval stages, was the dominant species. Resting catch method obtained the highest number of adult mosquitoes (67%), whereas ovitrap showed the highest catch for larval mosquitoes (84%). Zika virus was detected in both adults and larvae of Ae. albopictus together with adults of Culex gelidus, and Culex quinquefasciatus using the real-time reverse transcriptase polymerase chain reaction (PCR) technique. It was noteworthy that Ae. albopictus positive with ZIKV were caught and obtained from four types of collection method. By contrast, Cx. gelidus and Culex quinquefasciatus adults collected from sticky ovitraps were also found positive with ZIKV. This study reveals vital information regarding the potential vectors of ZIKV and the possibility of transovarian transmission of the virus in Malaysia. These findings will be essentials for vector control program managers to devise preparedness and contingency plans of prevention and control of the arboviral disease.

Zika virus, which is transmitted by Aedes aegypti mosquitoes and through sexual transmission, disproportionally affects the human fetus. Guatemala experienced a surge of Zika cases beginning in 2016. We conducted a qualitative study of community perceptions of the seriousness of Zika, as well as the effectiveness, feasibility, and collective efficacy of Zika prevention actions. Free listing elicited the preventive actions salient for 68 participants comprising pregnant women, men with a pregnant partner, and women likely to become pregnant; 12 focus group discussions in a highland and a lowland town explored other concepts through rank orderings of prevention practices depicted on cards. Participants’ initial concern about Zika, based on recent experience with chikungunya and high media coverage, diminished because of its mild symptoms and reduced media coverage. Participants identified more than 32 salient preventive actions, many of which are considered effective by programs. Participants ranked water storage container cleaning and regular unspecified cleaning of the house and its surroundings as highly effective, feasible, and of high collective efficacy; however, the actions lacked the specificity needed to effectively destroy mosquito eggs. Community-level removal of tires and discarded containers had lower collective efficacy than household-level implementation because of the municipal and community cooperation needed. Condom use, although salient for Zika prevention, was hindered by gender roles. The findings indicate space for increasing self-efficacy for condom use among fathers-to-be, abandoning nonspecific terms such as “cleaning” and “standing water,” increasing people’s skills in using bleach as an ovicide, and promoting antenatal care and family planning counseling.

The genitourinary tract was recently identified as a potential site of complications related to the congenital Zika syndrome (CZS). We provide the first report of a series of cryptorchidism cases in 3-year-old children with Zika-related microcephaly who underwent consultations between October 2018 and April 2019 as part of the follow-up of the children cohort of the Microcephaly Epidemic Research Group, Pernambuco, Brazil. Of the 22 males examined, eight (36.4%) presented with cryptorchidism. Among 14 undescended testis cases, 11 (78.6%) could be palpated in the inguinal region. Seven of the eight children had severe microcephaly. Conventional risk factors for cryptorchidism were relatively infrequent in these children. We hypothesize that cryptorchidism is an additional manifestation of CZS present in children with severe microcephaly. As in our cases, for most of the children, the testes were located in the inguinal region, and the possible mechanisms for cryptorchidism were gubernaculum disturbance or cremasteric abnormality.

We tested 700 serum samples collected throughout Panama from 2015 to 2016 for detecting antibodies and RNA of arboviruses. In convalescent specimens, microsphere immunoassay detected an antibody prevalence of 59.3% for dengue virus (DENV) and 30.3% for Zika virus (ZIKV), which included samples that were collected before the Panamanian surveillance system reported the first case of Zika in the country. For acute sera, the most common arbovirus was DENV with 18 positive samples (6%), followed by four (1.3%) of ZIKV and one (0.6%) of chikungunya virus (CHIKV). Our results indicate a change in the chronology of when ZIKV was first detected in Panama and stress the importance of integrating various approaches to enable improved surveillance of both endemic and emerging arboviruses.

Chronic hepatitis B virus (HBV) infection is a major public health problem in China. We evaluated the impact of psychosocial factors (stigma, disclosure, depression, and anxiety) on health-related quality of life (HRQoL) among people living with chronic HBV infection (CHB) in the city of Dalian, Liaoning Province, China. In this hospital-based cross-sectional study, 401 patients living with chronic HBV infection were enrolled as study participants. Study measures included the Beck depression and anxiety inventory, the WHO Quality of Life (WHOQOL-BREF) assessment, the Toronto Chinese HBV Stigma Scale, and disclosure of HBV status to sexual partners. The primary outcome was HRQoL score as measured by the WHOQOL-BREF. A linear regression model was used to examine the association between HRQoL and the potential risk factors including stigma, disclosure, depression, anxiety, and sociodemographic variables. Stigma, disclosure, depression, and anxiety were the covariates of interest. A majority of the participants were females (n = 251, 65.6%), married (81.6%), and had a college or higher degree (32.4%). Depression, anxiety, stigma, and disclosure of HBV infection were associated with low HRQoL in all four domains of the WHOQOL-BREF (physical, psychological, social, and environmental domains) (P < 0.05), when all psychological factors were included in the model separately. Depression was found to be independently associated with low HRQoL in people living with HBV, when all psychological factors were included in the model simultaneously (P < 0.0001). Our data indicate the urgent need for healthcare providers (HCPs) and policy-makers to implement psychological interventions to improve HRQoL among people living with CHB.

There have been various estimates of the prevalence of hepatitis B and C infections in Nigeria. Recent studies have shown the prevalence to be lower than previously reported. The different populations studied might be responsible for this. It is important to have a real population data that would inform the policies to be adopted for eradication. We set out to determine the prevalence, risk factors, and pattern of hepatitis B and C in Benue State, Central Nigeria. Four thousand and five (4,005) subjects, aged 1 year and older, were selected through a multistage random sampling to represent all parts of the state. Trained health workers administered a validated questionnaire. Rapid test kits were standardized and used in determining the prevalence of the respective viruses. Hepatitis B surface antigen (HBsAg) and antibodies to hepatitis C virus (anti-HCV) were found to be positive in 5% and 1%, respectively, of subjects screened. The prevalence varied from one local government area to another, with HBsAg being 8% in the highest to 2% in the lowest LGC, and anti-HCV being 3% in the highest and 0% in the lowest. Age, previous close contact with a patient, and multiple sex partners were the most important risk factors for hepatitis B virus (HBV) infection, whereas age and previous blood transfusion were the most important risk factors for hepatitis C virus (HCV) infection. HBV immunization may be having an impact in reducing the prevalence of the virus. Nigeria appears to be moving from high endemicity to the intermediate one.