The American Journal of Tropical Medicine and Hygiene - Current Issue

The tenth outbreak of Ebola virus disease (EVD) in North Kivu, the Democratic Republic of the Congo (DRC), was declared 8 days after the end of the ninth EVD outbreak, in the Equateur Province on August 1, 2018. With a total of 3,461 confirmed and probable cases, the North Kivu outbreak was the second largest outbreak after that in West Africa in 2014–2016, and the largest observed in the DRC. This outbreak was difficult to control because of multiple challenges, including armed conflict, population displacement, movement of contacts, community mistrust, and high population density. It took more than 21 months to control the outbreak, with critical innovations and systems put into place. We describe systems that were put into place during the EVD response in the DRC that can be leveraged for the response to the current COVID-19 global pandemic.

The ongoing pandemic COVID-19, caused by SARS-CoV-2, has already resulted in more than 3 million cases and more than 200,000 deaths globally. Significant clinical presentations of COVID-19 include respiratory symptoms and pneumonia. In a minority of patients, extrapulmonary organs (central nervous system, eyes, heart, and gut) are affected, with detection of viral RNA in bodily secretions (stool, tears, and saliva). Infection of such extrapulmonary organs may serve as a reservoir for SARS-CoV-2, representing a potential source of viral shedding after the cessation of respiratory symptoms in recovered patients or in asymptomatic individuals. It is extremely important to understand this phenomenon, as individuals with intermittent virus shedding could be falsely identified as reinfected and may benefit from ongoing antiviral treatment. The potential of SARS-CoV-2 infection to rapidly disseminate and infect extrapulmonary organs is likely mediated through the nonstructural and accessory proteins of SARS-CoV-2, which act as ligands for host cells, and through evasion of host immune responses. The focus of this perspective is the extrapulmonary tissues affected by SARS-CoV-2 and the potential implications of their involvement for disease pathogenesis and the development of medical countermeasures.

In response to the COVID-19 pandemic, in addition to the more routine public health measures, many countries have implemented “lockdowns”—closing borders, restricting international travel, and placing severe limitations on individual movement and group gatherings. While lockdowns may be an important tool to limit transmission, they come at a potentially great cost with regard to economic impact, mental health consequences, and increased morbidity and mortality from non–COVID-19 diseases. Furthermore, implementation of the required draconian measures may be difficult in some settings because of logistical, economic, and sociocultural impediments, especially in many low- and middle-income countries. Governments and health authorities must chart a course on how to “unlock” or control transmission where lockdowns are not feasible. “Precision physical distancing”—distancing tailored and optimized to specific physical, social, cultural, political, and economic contexts and to specific groups and settings—is proposed and discussed here as an important tool in the control of COVID-19. It has the advantages of being low cost, adaptable to diverse sociocultural and economic settings through community ownership and local action, and more easily monitored and potentially enforced than less precise measures. Precision physical distancing can be one important component of a sustainable long-term solution that is proportionate to the risk yet does not have a disproportionate impact on society and the economy, allowing a partial return to normal activities, with the community as an essential partner.

The novel coronavirus disease (COVID-19) pandemic has unveiled underlying health inequities throughout the United States. The pandemic has spread across U.S. states, affecting different vulnerable populations, including both inner-city and rural populations, and those living in congregate settings such as nursing homes and assisted-living facilities. In addition, since early April, there has been an increasing number of outbreaks of COVID-19 in jails and prisons. We describe three overlapping epidemiologic waves of spread of COVID-19 linked to three different kinds of structural vulnerabilities.

Most countries around the world have responded promptly to the novel coronavirus disease (COVID-19) challenge by adopting considered and scientifically guided strategies for its containment. However, the situation is more complex for nations where malaria is endemic, as they now have the additional burden of COVID-19. In such nations, the healthcare systems are either in the preparatory or containment phase of the current pandemic. This enforced, sudden, and sharp public health refocus is likely to result in the disruption of annual malaria control activities such as distribution of insecticide-impregnated bed nets, indoor residual spraying of insecticide, maintenance of malaria surveillance, and mass provision of antimalarial drugs. Nonetheless, we feel that the best facets of COVID-19 public health management can become new guiding principles in malaria-endemic countries to improve malaria control and hasten malaria elimination. Redirection against malaria of the best public health initiatives used in COVID-19 containment could fast-track the global goal of a malaria-free world. Such public health advancement could be one positive outcome from the scourge of COVID-19.

The COVID-19 pandemic highlights the multidimensional and inseparable connection between human health and environmental systems. COVID-19, similar to other emerging zoonotic diseases, has had a devastating impact on our planet. In this perspective, we argue that as humans continue to globalize and encroach on our surrounding natural systems, societies must adopt a “planetary health lens” to prepare and adapt to these emerging infectious diseases. This piece further explores other critical components of a planetary health approach to societal response, such as the seasonality of disease patterns, the impact of climate change on infectious disease, and the built environment, which can increase population vulnerabilities to pandemics. To address planetary health threats that cross international borders, such as COVID-19, societies must practice interdependence sovereignty and direct resources to organizations that facilitate shared global governance, and thus can enable us to adapt and ultimately build a more resilient world.

Because of the pandemic of COVID-19, the federal government of Nigeria has instituted a mandatory policy requiring everyone going out in public to wear face masks. Unfortunately, the Nigeria media is awash with images of misuse and abuse of face masks by the public, government officials, and healthcare workers. Medical masks are used widely in community settings amid reported scarcity within healthcare facilities. It is observed that some people wear face masks on their chin and neck, and mask wearers give no attention to covering their mouth and nose, especially when talking. Used face masks are kept with personal belongings or disposed indiscriminately in public spaces, leading to self and environmental contamination. Inappropriate use and disposal of face masks in Nigeria could promote the spread of the novel coronavirus in the country and negate the country’s efforts to contain the COVID-19 pandemic. In the implementation of the universal masking policy in Nigeria, federal and state governments ought to consider local applicability, feasibility, and sustainability, as well as identify and mitigate all potential risks and unintended consequences. Also critical is the need for intensive public sensitization and education on appropriate use and disposal of face masks in the country.

Globally, more than 4 million people have been infected with COVID-19, and more than 300,000 deaths have been reported across 188 countries. Concealment of one’s potential exposure to the virus has negative implications for the spread of COVID-19 across the socio-ecological spectrum, including the futility of contact-tracing efforts, exposure of frontline staff, and the spread of COVID-19 in the community. We draw lessons learned from HIV to discuss stigma and the attribution of blame surrounding the phenomenon of concealment of one’s potential exposure to COVID-19 using a socio-ecological perspective. This article also illustrates the psychosocial aspect of the disease, and the negative repercussions of concealment of potential exposure on transmission in the community and to front-liners, healthcare resources, and outbreak containment.

In the most recent Brazilian yellow fever (YF) outbreak, a group of clinicians and researchers initiated in mid-January 2018 a considerable effort to develop a multicenter randomized controlled clinical trial to evaluate the effect of sofosbuvir on YF viremia and clinical outcomes (Brazilian Clinical Trials Registry: RBR-93dp9n). The approval of this protocol had urgency given the seasonal/short-lived pattern of YF transmission, large number of human cases, and epidemic transmission at the outskirts of a large urban center. However, many intricacies in the research regulatory and ethical submission systems in Brazil were indomitable even under such pressing conditions. By April 2018, we had enrolled 29 patients for a target sample size of 90 participants. Had enrollment been initiated 3 weeks earlier, an additional 31 patients could have been enrolled, reaching the prespecified sample size for the interim analysis. This recent experience highlights the urgent need to improve local preparedness for research in the setting of explosive outbreaks, as has been seen in the last few years in different countries.

A long-held assumption has been that nearly all malaria deaths in high-transmission areas are of children younger than 5 years and pregnant women. Most global malaria mortality estimates incorporate this assumption in their calculations. In 2010, the Indian Million Death Study, which assigns cause of death by verbal autopsy (VA), challenged the reigning perception, producing a U-shaped mortality age curve, with rates rising after age 45 years in areas of India with substantial malaria transmission. Similar patterns are seen in Africa in the International Network for the Demographic Evaluation of Populations and Their Health (INDEPTH) network, also relying on VA. Whether these results are accurate or are misidentified deaths can be resolved by improving the evidence for assigning causes for adult acute infectious deaths in high malaria transmission areas. The options for doing so include improving the accuracy of VA and adding postmortem biological evidence, steps we believe should be initiated without delay.

Since late December 2019, the world has been challenged with an outbreak of COVID-19. In Thailand, an upper middle–income country with a limited healthcare infrastructure and restricted human resources, nearly 3,000 confirmed COVID-19 cases have been reported as of early May 2020. Public health policies aimed at preventing new COVID-19 cases were very effective in halting the pandemic in Thailand. Case fatality in Thailand has been low (1.7%), at least in part due to early stratification according to risk of disease severity and timely initiation of supportive care with affordable measures. We present our initial experience with COVID-19 in Thailand, focusing on several aspects that may have played a crucial role in curtailment of the pandemic, and elements of care for severely ill COVID-19 patients, including stratification, isolation, and affordable diagnostic approaches and supportive care measures. We also discuss local considerations concerning some proposed experimental treatments.

Murine typhus is a neglected but widespread infectious disease that results in acute fever. The immunofluorescence assay (IFA) is the “gold standard” to identify IgM or IgG antibodies, although there is a lack of standardization in methodologies. The objective of this review is to summarize 1) the differences in published methodologies, 2) the diagnostic cutoff titers, and 3) the justification of diagnostic cutoffs. Searches were performed by combining the following search terms: “murine typhus,” “rickettsia typhi,” “immunofluorescence,” “IFA,” and “serologic” with restrictions (i.e., “rickettsia typhi” or “murine typhus,” and “IFA” or “immunofluorescence,” or “serologic*”). The search identified 78 studies that used IFA or immunoperoxidase assay (IIP) antibody cutoffs to diagnose murine typhus, 39 of which were case series. Overall, 45 studies (57.7%) provided little to no rationale as to how the cutoff was derived. Variation was seen locally in the cutoff titers used, but a 4-fold or greater increase was often applied. The cutoffs varied depending on the antibody target. No consensus was observed in establishing a cutoff, or for a single-value diagnostic cutoff. In conclusion, there is a lack of consensus in the establishment of a single-value cutoff. Further studies will need to be executed at each distinct geographic location to identify region-specific cutoffs, while also considering background antibody levels to distinguish between healthy and infected patients.

Hookworm infections are classified as the most impactful of the human soil-transmitted helminth (STH) infections, causing a disease burden of ∼4 million disability-adjusted life years, with a global prevalence of 406–480 million infections. Until a decade ago, epidemiological surveys largely assumed Necator americanus and Ancylostoma duodenale as the relevant human hookworm species implicated as contributing to iron-deficiency anemia. This assumption was based on the indistinguishable morphology of the Ancylostoma spp. eggs in stool and the absence of awareness of a third zoonotic hookworm species, Ancylostoma ceylanicum. The expanded use of molecular diagnostic assays for differentiating hookworm species infections during STH surveys has now implicated A. ceylanicum, a predominant hookworm of dogs in Asia, as the second most common hookworm species infecting humans in Southeast Asia and the Pacific. Despite this, with the exception of sporadic case reports, there is a paucity of data available on the impact of this emerging zoonosis on human health at a population level. This situation also challenges the current paradigm, necessitating a One Health approach to hookworm control in populations in which this zoonosis is endemic. Here, we have summarized the available research studies and case reports on human A. ceylanicum infections in Southeast Asia and the Pacific after 2013 using a systematic review approach. We summarized eight research articles and five clinical case studies, highlighting the importance of future in-depth investigation of zoonotic A. ceylanicum infections using sensitive and cost-effective diagnostic tools.