Tropical Medicine and Infectious Disease

Purpose: Rotavirus (RV) ranked first among infectious diarrhea-causing pathogens in Yantai from 2017 to 2019. This study investigated the seroserotypes of RV in Yantai, Shandong, from 2017 to 2019 to identify the dominant serotypes and explore the epidemic pattern, aiming to effectively reduce the infection rate, better guide vaccination, and help in epidemiological prevention and control. Methods: A total of 2227 human diarrhea samples were collected from 2017 to 2019 in Yantai. The VP7 (G serotype) and VP4 (P serotype) genes of 467 RV-positive samples were amplified using two-round nested reverse transcription–polymerase chain reaction for G/P genotyping. Results: The genotyping results of RV in Yantai from 2017 to 2019 revealed that G9 was the dominant serotype for all G serotypes, P[8] was the dominant serotype for all P serotypes, and G9P[8] was the dominant serotype for all G/P combinations. G9 serotype accounted for 60.84%, 95.65%, and 83.76% of the total RV samples collected in 2017, 2018, and 2019, respectively. P[8] accounted for 75.52%, 94.69%, and 88.89% of the RV-positive samples collected in 2017, 2018, and 2019, respectively. G9P[8] accounted for 60.84%, 94.69%, and 83.76% of the total RV samples collected in 2017, 2018, and 2019, respectively. Of the total 467 samples from 2017 to 2019, G2P[4] accounted for 3.64% (17/467), G3P[8] for 1.28% (6/467), and G1P[8] for 0.86% (4/467). Conclusion: This study revealed the epidemiological characteristics of RV infection and the development pattern of dominant serotypes in Yantai in recent years, guiding the selection of RV vaccines. The prioritization of vaccines containing G9 serotype for infants in Yantai in recent years is recommended. Full article

Tuberculosis (TB) is one of the ten infectious diseases that cause the highest amount of human mortality and morbidity. This infection, which is caused by a single pathogen, Mycobacterium tuberculosis, kills over a million people every year. There is an emerging problem of antimicrobial resistance in TB that needs urgent treatment and management. Tuberculosis treatment is complicated by its complex drug regimen, its lengthy duration and the serious side-effects caused by the drugs required. There are a number of critical issues around drug delivery and subsequent intracellular bacterial clearance. Drugs have a short lifespan in systemic circulation, which limits their activity. Nanomedicine in TB is an emerging research area which offers the potential of effective drug delivery using nanoparticles and a reduction in drug doses and side-effects to improve patient compliance with the treatment and enhance their recovery. Here, we provide a minireview of anti-TB treatment, research progress on nanomedicine and the prospects for future applications in developing innovative therapies. Full article

The pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been responsible for approximately 6.8 million deaths worldwide, threatening more than 753 million individuals. People with severe coronavirus disease-2019 (COVID-19) infection often exhibit an immunosuppression condition, resulting in greater chances of developing co-infections with bacteria and fungi, including opportunistic yeasts belonging to the Saccharomyces and Candida genera. In the present work, we have reported the case of a 75-year-old woman admitted at a Brazilian university hospital with an arterial ulcer in the left foot, which was being prepared for surgical amputation. The patient presented other underlying diseases and presented positive tests for COVID-19 prior to hospitalization. She received antimicrobial treatment, but her general condition worsened quickly, leading to death by septic shock after 4 days of hospitalization. Blood samples collected on the day she died were positive for yeast-like organisms, which were later identified as Saccharomyces cerevisiae by both biochemical and molecular methods. The fungal strain exhibited low minimal inhibitory concentration values for the antifungal agents tested (amphotericin B, 5-flucytosine, caspofungin, fluconazole and voriconazole), and it was able to produce important virulence factors, such as extracellular bioactive molecules (e.g., aspartic peptidase, phospholipase, esterase, phytase, catalase, hemolysin and siderophore) and biofilm. Despite the activity against planktonic cells, the antifungals were not able to impact the mature biofilm parameters (biomass and viability). Additionally, the S. cerevisiae strain caused the death of Tenebrio molitor larvae, depending on the fungal inoculum, and larvae immunosuppression with corticosteroids increased the larvae mortality rate. In conclusion, the present study highlighted the emergence of S. cerevisiae as an opportunistic fungal pathogen in immunosuppressed patients presenting several severe comorbidities, including COVID-19 infection. Full article

Tungiasis is a neglected disease caused by the sand flea Tunga penetrans, and dogs are considered the main reservoirs in Brazil. This study aimed to identify the role of dogs as tungiasis dispersers and to investigate the presence of T. penetrans in the soil of an endemic tourist area. Nine dogs infected by T. penetrans were included in this study and received GPS collars to analyze their movement through the village. Duplicate sand samples were collected in different areas of the community. Those areas were classified as peridomicile (n = 110), open area (n = 110), beach (n = 50), and river (n = 58). The analysis of the points recorded by the collars showed that the dogs roamed throughout the community, potentially facilitating the spread of the disease. Samples contaminated with developmental forms of the parasite were found in the circulation area of three dogs. Adult fleas were found in 3/328 samples. These data emphasize that infected dogs’ roaming can influence the fleas’ dispersion in the soil. Statistically, none of the study variables had a significant correlation (p > 0.5) with the presence of T. penetrans in the area analyzed. This study was the first to assess infected dogs’ role as tungiasis propagators. Full article

Leptospirosis is an important zoonosis worldwide. This disease affects numerous animal species, some of them are classified as “maintenance hosts”, and others are categorized as “incidental hosts”. Humans are at risk of becoming infected by having contact with domestic and wild animals. In this paper, general aspects of the etiology and transmission of leptospirosis are addressed, data regarding the clinical presentation of the pathology in humans and animals are also presented, and the results of some epidemiological studies on leptospirosis carried out in Chile in different animal species and humans are summarized through a bibliographic review of the literature. The research on domestic canines and horses stands out in terms of their number in the country, with prevalences between 12.0% and 59.1% in dogs and from 23.3% to 65.4% in equids. Studies have been performed on domestic felines in recent years with frequencies ranging from 3.0% to 25.2%, as well as on wild animals (mainly in mammals). In pigs, cattle, sheep, and goats, the information is scarce, with little updated research dating back several decades and variable prevalence rates, which are generally high, except for in sheep. Leptospirosis is a disease of varied etiology in terms of infecting species, serovars and serogroups, which influences its epidemiology, and its prevalence is variable in different animals. An increase in the awareness given to this pathology in human and veterinary public health is required, as well as more scientific studies in Chile, to update the existing knowledge. Full article

(1) Background: Angola is among the high-burden countries with malaria cases globally. After 2013, we suspected an increase in the number of malaria cases in Cubal (Angola), previously in decline. Our objective was to evaluate the incidence rate in Cubal, overall and by neighborhood, for 2014, 2015, and 2016. (2) Methods: A retrospective, observational study was performed in Cubal (Angola) from January 2014 to December 2016, including all patients with a microbiologically confirmed diagnosis, treated at Cubal’s Hospitals for this period of time. The principal variables calculated were the incidence rates of 2014, 2015, and 2016 in Cubal (overall and by neighborhood). (3) Results: There were 3249 malaria cases. The incidence rates were 2.27, 10.73, and 12.40 cases per 1000 inhabitants in 2014, 2015, and 2016, respectively. In the neighborhood, Hamavoko-Kasseke, there was a 10.73-fold increase in incidence during this period. Additionally, Hamavoko-Kasseke presents an anomalous distribution of malaria cases. (4) Conclusions: We observed an increase in the incidence of malaria in Cubal during the three-year study period. The case distribution was highly heterogeneous with hyperendemic areas, and we found a chronobiological association between the construction of a civil engineering project. This information could be useful for deciding which malaria control strategies must be implemented in this area. Full article

Two primary vaccines for coronavirus disease 2019 (COVID-19) have been rolled out in the mass vaccination campaign that started simultaneously with the spread of the delta variant. To explore the vaccines’ effect on reducing viral load and disease severity, we conducted a retrospective cohort study in Thai patients aged ≥ 18 years who were confirmed COVID-19 positive by RT-PCR. Compared to unvaccinated patients, Ct values and the number of severe cases among vaccine regimens were analyzed. Ct values of vaccinated patients were not significantly different from unvaccinated patients, despite an increase of Ct values in a booster dose. The adjusted odd ratio for prevention of delta-related severe diseases was 0.47, 95% CI: 0.30–0.76 and 0.06, 95% CI: 0.01–0.45 after receiving one dose and two doses, respectively. No severe illness was found in booster-vaccinated individuals. Focusing on the vaccine types, one dose of ChAdOx1 nCoV-19 gave significant protection, whereas one dose of CoronaVac did not (0.49, 95% CI: 0.30–0.79, p = 0.003 vs. 0.28, 95% CI: 0.04–2.16, p = 0.223). Two-dose vaccination showed robust protective effects in all subpopulations regardless of vaccine type. Vaccinations with two primary vaccines could not reduce viral load in patients with COVID-19, but could prevent severe illness. Full article

Tuberculosis (TB) is a chronic infectious disease that remains to be a primary health concern globally. The Philippines is among the top TB-burdened countries. Workplace TB prevention and control programs are essential to ensure the health and safety of workers and economic security. There remains a knowledge gap regarding the Philippine workplace TB prevention and control program implementation. This qualitative study involving key informant interviews reviewed the implementation of the workplace TB program in selected companies in a high TB burden region in Eastern Philippines. Results were presented under four themes in accordance with the components of the workplace TB policy: preventive strategies, medical management, data recording and reporting, and social policy. Various good practices, opportunities, and challenges in the implementation of the workplace TB program were identified. There is a need to strengthen the enforcement of policy across different components. Compliance with guidelines on preventive strategies and recording and reporting schemes needs to be intensified. Coordination across different levels and agencies may also be enhanced to allow more efficient implementation. Increased awareness of corporate decision-makers may improve company ownership of the program leading to improved implementation while increased awareness of employees on their rights and entitlements may likewise enhance compliance. Full article

Hepatitis C virus (HCV) chronic infection is a major causative factor for several chronic liver diseases, including liver cirrhosis, liver cell failure, and hepatocellular carcinoma. The HCV has seven major genotypes. Genotype 4 is the most prevalent genotype in the Middle East, including Saudi Arabia, followed by genotype 1. The HCV genotype affects the response to different HCV treatments and the progression of liver disease. Currently, combinations of direct-acting antiviral drugs (DAAs) approved for the treatment of HCV achieve high cure rates with minimal adverse effects. Because real-world data from Saudi Arabia about the efficacy of DAAs are still limited, this study was conducted to assess the effectiveness of DAAs in treating patients with chronic hepatitis C and to identify the variables related to a sustained virologic response (SVR) in a real-world setting in Saudi Arabia. This prospective cohort study included 200 Saudi patients with chronic HCV who were 18 years of age or older and had been treated with DAAs at King Abdul-Aziz Specialized Hospital in Taif, Saudi Arabia, between September 2018 and March 2021. The response to treatment was assessed by whether or not an SVR had been achieved at week 12 post treatment (SVR12). An SVR12 was reached in 97.5% of patients. SVR12 rates were comparable for patients of different ages, between men and women, and between patients with and without cirrhosis. In addition, the SVR12 rates did not differ according to the infecting HCV genotype. In this study, the presence of cirrhosis and the patient’s gender were independent predictors of who would not reach an SVR12 (known here as the non-SVR12 group) according to the results of univariate and multivariate binary logistic regression analyses based on the determinants of SVR12. In this population of patients with chronic HCV infection, all DAA regimens achieved very high SVR12 rates. The patients’ gender and the presence of cirrhosis were independent factors of a poor response. Full article

The Thai government implemented COVID-19 booster vaccines to prevent morbidity and mortality during the spreading of the Omicron variant. However, little is known about which types of vaccine should be invested in as the booster dose for the Thai population. This study aims to investigate the most cost-effective COVID-19 vaccine for a booster shot as empirical evidence for Thai policymakers. This study applied a stochastic simulation based on a compartmental susceptible-exposed-infectious-recovered model and included system dynamics in the model. We evaluated three scenarios: (1) No booster, (2) A viral vector vaccine as the booster dose, (3) An mRNA vaccine as the booster dose. The incremental cost-effectiveness ratio (ICER) was calculated based on provider perspectives. We found the number of cases in scenarios with viral vector and mRNA booster doses to be lower than in the non-booster group. Likewise, the number of deaths in the viral vector and the mRNA booster scenarios was threefold lower than in the no-booster scenario. Moreover, the estimated grand cost for the no-booster scenario was over 100 billion baht, while viral vector and mRNA scenario costs were 70 and 64.7 billion baht, respectively. ICER shows that viral vector and mRNA scenarios are more cost-effective than the no-booster scenario. Viral vector booster shot appeared to be slightly more cost-effective than mRNA booster shot in terms of death aversion. However, being boosted by an mRNA vaccine seemed slightly more cost-effective than a viral vector vaccine concerning case aversion. In conclusion, policies to promote COVID-19 booster shots in the Thai population by either mRNA or viral vector vaccines are likely to be worthwhile for both economic and public health reasons. Full article

In March 2020, WHO declared Coronavirus Disease 2019 (COVID-19) as a global pandemic, which had a major impact on all mass gatherings (MG), including the Hajj. This has an impact for the government, as the party organizing the pilgrimage can make more mature preparations for a more optimal implementation of the pilgrimage. This study aimed to evaluate hygiene and health coaching for community readiness to perform the Hajj during an ongoing COVID-19 pandemic in Indonesia. We used a mixed qualitative and quantitative method, in which the quantitative component used an analytic cross-sectional design with a questionnaire given to 2425 pilgrims, while the qualitative component was carried out through Focus Group Discussion. During the pandemic, all hygiene and health coaching, including guidance, was carried out in three types of distance learning, called “online”, “offline (face-to-face)”, and “combination”. This study shows that face-to-face health coaching is low (50.5%), while online coaching is high (70.0%). The total fraction of pilgrims who participated in blended coaching sessions was 55.1%, and the highest frequency of coaching was under four times (38.7%). However, in its implementation, there is still no integration between programs. There is quite a lot of health information given to pilgrims, but the material still varies between regions. Information on guidelines for preventing and transmitting COVID-19 for officers and pilgrims has not been fully socialized. There exists an urgent need to establish messages that are clear, meaningful, empathetic, consistent, and in context in order to achieve health improvement of pilgrims. Full article

Globally, it is estimated that one-quarter of the world’s population is latently infected with Mycobacterium tuberculosis (Mtb), also known as latent tuberculosis infection (LTBI). Recently, this condition has been referred to as tuberculosis infection (TBI), considering the dynamic spectrum of the infection, as 5–10% of the latently infected population will develop active TB (ATB). The chances of TBI development increase due to close contact with index TB patients. The emergence of multidrug-resistant TB (MDR-TB) and the risk of development of latent MDR-TB has further complicated the situation. Detection of TBI is challenging as the infected individual does not present symptoms. Currently, there is no gold standard for TBI diagnosis, and the only screening tests are tuberculin skin test (TST) and interferon gamma release assays (IGRAs). However, these tests have several limitations, including the inability to differentiate between ATB and TBI, false-positive results in BCG-vaccinated individuals (only for TST), false-negative results in children, elderly, and immunocompromised patients, and the inability to predict the progression to ATB, among others. Thus, new host markers and Mtb-specific antigens are being tested to develop new diagnostic methods. Besides screening, TBI therapy is a key intervention for TB control. However, the long-course treatment and associated side effects result in non-adherence to the treatment. Additionally, the latent MDR strains are not susceptible to the current TBI treatments, which add an additional challenge. This review discusses the current situation of TBI, as well as the challenges and efforts involved in its control. Full article

Background: Drug utilisation studies are relevant for the analysis of prescription rationality and are pertinent in today’s context of the increasing burden of antimicrobial resistance. Prescriptions for patients with diarrhoea or Acute Respiratory Infection (ARI) have been analysed in this study to understand the prescription pattern among various categories of prescribers in two tertiary care centers. Methods: This cross-sectional study was conducted from August 2019 to December 2020 in the medicine and pediatrics outpatient departments of two government teaching hospitals in West Bengal, India. A total of 630 prescriptions were evaluated against WHO standards. Prescriptions were assessed by a ‘Rational Use of Medicine Consensus committee’ approach. Results: The Fixed Dose Combination (FDC) was used in half of the patients (51%). Both the generic prescription (23.3%) and adherence to hospital formulary rates (36.5%) were low. The antibiotics prescription rate was high (57%), and it was higher for diarrhoea than ARI. Deviations from the standard treatment guidelines were found in 98.9% of prescriptions. Deviations were commonly found with prescriptions written by the junior doctors (99.6%). Conclusion: Irrational prescribing patterns prevail in tertiary care centers and indicate the necessity of awareness generation and capacity building among prescribers regarding AMR and its unseen consequences. Full article

The mosquito-borne disease caused by the Rift Valley Fever Virus (RVFV) is a viral hemorrhagic fever that affects humans and animals. In 1987, RVFV emerged in Mauritania, which caused the first RVFV outbreak in West Africa. This outbreak was shortly followed by reported cases in humans and livestock in Senegal. Animal trade practices with neighboring Mauritania suggest northern regions of Senegal are at high risk for RVF. In this study, we aim to conduct a molecular and serological survey of RVFV in humans and livestock in Agnam (northeastern Senegal) by RT-PCR (reverse transcription real-time polymerase chain reaction) and ELISA (Enzyme-Linked Immunosorbent Assay), respectively. Of the two hundred fifty-five human sera, one (0.39%) tested RVFV IgM positive, while fifty-three (20.78%) tested positive for RVFV IgG. For animal monitoring, out of 30 sheep recorded and sampled over the study period, 20 (66.67%) showed seroconversion to RVFV IgG antibodies, notably during the rainy season. The presence of antibodies increased significantly with age in both groups (p < 0.05), as the force of RVF infection (FOI), increased by 16.05% per year for humans and by 80.4% per month for livestock sheep. This study supports the usefulness of setting up a One Health survey for RVF management. Full article

Dengue cases have been rising in recent years. In 2019 alone, over 658,301 of the 5.6 million reported cases originated from Southeast Asia (SEA). Research has also shown detrimental outcomes for pregnant infected women. Despite this, existing literature describing dengue’s effects on pregnancy in SEA is insufficient. Through this narrative review, we sought to describe dengue’s effects on pregnancy systemically and emphasize the existing gaps in the literature. We extensively searched various journals cited in PubMed and Ovid Medline, national clinical practice guidelines, and governmental reports. Dengue in pregnancy increases the risk of pre-eclampsia, Dengue Hemorrhagic Fever (DHF), fetal distress, preterm delivery, Caesarean delivery, and maternal mortality. Vertical transmission, intrauterine growth restriction, and stillbirth are possible sequelae of dengue in fetuses. We found that trimester-specific physiological impacts of dengue in pregnancy (to both mother and child) and investigations and management methods demanded further research, especially in the SEA region. Full article

There are different area-based factors affecting the COVID-19 mortality rate in urban areas. This research aims to examine COVID-19 mortality rates and their geographical association with various socioeconomic and ecological determinants in 350 of Tehran’s neighborhoods as a big city. All deaths related to COVID-19 are included from December 2019 to July 2021. Spatial techniques, such as Kulldorff's SatScan, geographically weighted regression (GWR), and multi-scale GWR (MGWR), were used to investigate the spatially varying correlations between COVID-19 mortality rates and predictors, including ­­air pollutant factors, socioeconomic status, built environment factors, and public transportation infrastructure. The city's downtown and northern areas were found to be significantly clustered in terms of spatial and temporal high-risk areas for COVID-19 mortality. The MGWR regression model outperformed the OLS and GWR regression models with an adjusted R² of 0.67. Furthermore, the mortality rate was found to be associated with air quality (e.g., NO₂, PM₁₀, and O₃); as air pollution increased, so did mortality. Additionally, the aging and illiteracy rates of urban neighborhoods were positively associated with COVID-19 mortality rates. Our approach in this study could be implemented to study potential associations of area-based factors with other emerging infectious diseases worldwide. Full article

COVID-19 patients occasionally present with diarrhoea. Our objective was to estimate the risk of developing the severe disease in COVID-19 patients with and without diarrhoea and to provide a more precise estimate of the prevalence of COVID-19-associated digestive symptoms. A total of 88 studies (n = 67,794) on patients with a COVID-19 infection published between 1 January 2020 and 20 October 2022 were included in this meta-analysis. The overall prevalence of digestive symptoms was 27% (95% confidence interval (CI): 21–34%; I² = 99%). According to our data, the pooled prevalence of diarrhoea symptoms in the 88 studies analysed was 17% (95% CI: 14–20%; I² = 98%). The pooled estimate of nausea or vomiting in a total of 60 studies was 12% (95% CI: 8–15%; I² = 98%). We also analysed 23 studies with eligible individuals (n = 3800) to assess the association between the disease severity and diarrhoea. Individuals who had diarrhoea were more likely to have experienced severe COVID-19 (odds ratio: 1.71; 95% CI: 1.31–2.24; p < 0.0001; I² = 10%). Gastrointestinal symptoms and diarrhoea are frequently presenting COVID-19 manifestations that physicians should be aware of. Full article

The recent COVID-19 pandemic has drawn attention to health and economics worldwide. Initially, diseases only ravage local populations, while a pandemic could aggravate global economic burdens. Lopinavir/Ritonavir is an anti-HIV drug that was used on small scale patients during SARS, but its effectiveness for COVID-19 treatment is still unclear. Previous studies or meta-analysis have retrieved clinical data of subgroup analysis to evaluate the efficacy and safety of Lopinavir/Ritonavir for the treatment of COVID-19 in a few affected regions. However, geographical diversity and small number of studies bias correction were not achieved in such subgroup analysis of published meta-analysis. The present study demonstrates a practical approach in refining the binary outcome for COVID-19 treatment of Lopinavir/Ritonavir according to geographical location diversity and small number of studies (less than or equal to five) for subgroup analysis. After performing practical approach, the risk of adverse event with LPV/RTV for treatment of COVID-19 becomes nonsignificant compared to previous meta-analysis. Furthermore, we also notice heterogeneity of random effect of meta-analysis may be declined after proposed adjustment. In conclusion, proposed practical approach is recommend for performing a subgroup analysis to avoid concentration in a single geographical location and small number of studies bias. Full article