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A mathematical model for the transmission dynamics of silicosis in a mining environment is designed and its qualitative analysis is given. The model takes into account the severity of silica dust exposure in a mining environment. The whole analysis is done in both fractional differentiation and classical integer calculus. In the former case, the Haar wavelet numerical scheme is used to solve the model and perform graphical representations. In the integer calculus case, it is shown that the disease free and endemic equilibria are globally asymptotically stable in the absence as well as in the presence of silica dust particles in the air, respectively. The epidemiological implications of these results are discussed. Numerical simulations are presented to support the theoretical analysis. In fractional differentiation, we show graphically via the Haar wavelet scheme the convergence to the disease free-equilibrium and the global stability of the endemic equilibrium, results successfully confirmed analytically via the classical integer analysis.

In this paper, we develop an in-host mathematical model of snakebite envenoming that includes tissue, red blood and platelet cells of humans as specific targets of different kinds of toxins in the snake venom. The model is use to study some harmful effects of cytotoxic and hemotoxic snake venom on their target cells under the influence of snake antivenom. The model has two equilibrium points, namely, trivial and venom free. It has been shown that both the equilibrium points are globally asymptotically stable and numerical simulations illustrate the global asymptotic stability of the venom free equilibrium point. Furthermore, simulations reveal the importance of administering antivenom to avert the possible damage from venom toxins on the target cells. It is also shown through simulation that administering the required dose of antivenom can lead to the elimination of venom toxins within one week. Therefore, we recommend the administration of an adequate dose of antivenom therapy as it helps in deactivating venom toxins faster and consequently enhances the recovery time.

This paper presents a mathematical model with time delay for the transmission dynamics of zoonotic visceral leishmaniasis (ZVL which is caused by protozoan parasite leishmania infantum and transmitted by female sandflies). Qualitative analysis of the ODE version of the model reveals that the disease-free equilibrium of the model is globally asymptotically stable when the basic reproduction number, R0, is less than unity. Using time delay as a bifurcation parameter in the delay-differential version of the model, it has been shown that the incubation period has a significant effect on the stability of the equilibria and we derived the condition for Hopf bifurcation to occur.

Biomedical HIV research is growing in West Africa, but biostatistical expertise is lagging. The Vanderbilt-Nigeria Biostatistics Training Program (VN-BioStat) seeks to establish a research and training platform for biostatisticians doing HIV-related research in Nigeria. The objectives of the program are: (i) Host two Nigerian data scientists per year (a total of 10 over 5 years) at Vanderbilt University Medical Center to gain hands-on biostatistics training and experience via one-year fellowships. Eligible trainees will be junior investigators with PhDs or nearing completion of their PhDs in statistics or related fields, including mathematics and computer science. (ii) Conduct annual workshops in Nigeria to provide biostatistics training. Trainees will undertake biostatistics coursework and hands-on training and participate in mentorship as biostatisticians involved in HIV research. Trainees will be at Vanderbilt for a full year and be part of an active biostatistics department. They will be immersed in a dry-lab HIV biostatistics project in collaboration with a Nigerian HIV research project and lead a methodologically focused research project. They will also participate in a one-month research training/grant writing program in Nashville. The VN-BioStat program will build on the existing momentum of ongoing initiatives to enhance research capacity in Nigeria by developing biostatistics leadership. VN-BioStat trainees will interact with investigators from Nigeria to provide collaborative biostatistical assistance with study design and data analysis, thus gaining real-world experience that will benefit the trainees and the broader research community in Nigeria.

Newborn screening for sickle cell disease (SCD) is sparse in sub-Saharan Africa. The leadership of the Aminu Kano Teaching Hospital (AKTH) in Kano, Nigeria, with the support of local religious authorities, established a groundbreaking SCD newborn screening program that has become the standard of care for pregnant women and their newborns. Our program includes (1) prenatal genetic counseling for all pregnant women in the antenatal clinic, (2) newborn screening, (3) postnatal genetic counseling for parents of newborns diagnosed with SCD and SCT, and (4) referral of newborns with SCD for follow-up in the SCD Comprehensive Care Clinic by 3 months of age. From September 2020 to December 2023, the team screened 7530 infants for SCD at the AKTH, identifying 126 (1.7%) infants with SCD and 1546 (20.5%) with SCT. Of these, 93 (73.8%) newborns with SCD received individualized genetic counseling, and 43 (46%) were referred to the SCD Comprehensive Care Clinic before 3 months. Group genetic counseling was provided to the parents of 778 (50.3%) of newborns identified with SCT. The SCD newborn screening at the AKTH is now standard care, indicating the viability of sustaining an SCD newborn screening program that provides pre- and postnatal genetic counseling and comprehensive SCD care within a low-income setting.

Background: Breast cancer (BC) is one of the major causes of death worldwide. It is the most common cause of death before the age of 70 years. The incidence and mortality of BC are rapidly increasing, posing great challenges to the health system and economy of every nation., Methodology: A cross-sectional analytical study was conducted at the Department of Pathology and Clinical Laboratory of the French Medical Institute for Mothers and Children (FMIC) to demonstrate the association of human epidermal growth factor receptor 2 (Her2/Neu) and estrogen receptor (ER)/ progesterone receptor (PR) with clinical as well as pathological parameters among women with BC. A consecutive nonprobability sampling method was used for this study over a span of one and a half years., Results: One hundred twenty participants diagnosed with breast cancer were included in the study. The mean age at diagnosis was 44.58 ± 11.16 years. Out of the total patients, 68 (56.7%) were above 40 years old, 108 (90%) were married, 94 (78.3%) were multiparous, and 88 (73.3%) had a history of breastfeeding. 33.3% of cases were within the age range of menopause (40-50 years). The positive expression rates of ER, PR, and Her2/neu were found to be 48.8%, 44.6%, and 44.6%, respectively, and Her2/neu overexpression was found to be higher among ER/PR-negative cases., Conclusion: In our study, we demonstrated that among Afghan women, grade II invasive ductal carcinoma, not otherwise specified, was the most common type of BC and frequently affected women above the age of 40. We also revealed that the percentage of negative ER (50.4%), negative PR (54.4%), and concordant ER/PR-negative cases were high compared to other possibilities. Additionally, the study revealed that expression of Her2/neu was in contrast with the expression of ER and PR receptors. The findings of our study still support the importance of performing immunohistochemical stains for hormonal receptor classification in terms of better clinical outcomes and prognosis., (© 2024. The Author(s).)

Competing Interests: None declared

In Afghanistan, there are no reliable epidemiological data available about thyroid cytopathology and its possible relationship with the age and gender of patients. Therefore, we conducted this study to outline this relationship and the importance of fine needle aspiration cytology in this regard. A retrospective review study was conducted including 686 consecutive medical records of thyroid nodules diagnosed by fine needle aspiration cytology in a span of five years. Out of 686 consecutive patients with thyroid nodules included in this study, 566 were females and 120 were males. Most of the thyroid nodules diagnosed were benign lesions with female predominance. These nodules were commonly arising in between 3rd and 6th decades of life in both the genders with mean age of 42 ± 13 years in females and 52 ± 15 years in males. Thyroid malignancy was commonly diagnosed in middle-age females, however in males, it was frequently diagnosed in older age with a peak at 7th decade. Most of the malignant nodules were solid and complex with no purely cystic nature. In both the genders, thyroid nodules were commonly arising in the right thyroid lobe (52.3%), followed by left (35.7%), isthmus (8.7%) and bilateral (3.2%). Fine needle aspiration cytology remains the modality of choice for the diagnostic evaluation of nodular lesions of thyroid. In contrast to the data reported around the world, thyroid malignancies, in our study, were diagnosed in relatively older age groups with peak incidence in the 5th decade of life for females and 7th decade for males., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

We tested the hypothesis that fixed oral moderate-dose hydroxyurea (20 mg/kg per day) for initial treatment of secondary stroke prevention results in an 80% relative risk reduction of stroke or death when compared with fixed oral low-dose hydroxyurea (10 mg/kg per day) in a phase 3 double-blind, parallel-group, randomized controlled trial in children with sickle cell anemia (SCA) living in Nigeria. A total of 101 participants were randomly allocated to low-dose (n = 49) and moderate-dose (n = 52) hydroxyurea treatment groups. The median participant follow-up was 1.6 years (interquartile range, 1.0-2.3), with a planned minimum follow-up of 3.0 years. A total of 6 recurrent strokes and 2 deaths vs 5 recurrent strokes and 3 deaths occurred in the low- and moderate-dose groups, respectively. The incidence rate ratio (IRR) of the primary outcome measure of stroke or death in the low- and moderate-dose hydroxyurea treatment groups was 0.98 (95% confidence interval [CI], 0.32-3.00; P = .97). The trial was stopped early owing to no clinical difference in the incidence rates of the primary outcome measure. The incidence rates of recurrent strokes were 7.1 and 6.0 per 100 person-years in the low- and moderate-dose groups, respectively, (IRR, 1.18; 95% CI, 0.30-4.88; P = .74). As a measure of adherence to the oral hydroxyurea therapy, the median percent of returned pills was 3.0% and 2.6% in the low- and moderate-dose groups, respectively. No participant had hydroxyurea therapy stopped for myelosuppression. For children with SCA in low-income settings without access to regular blood transfusion therapy, initial low-dose hydroxyurea is a minimum known efficacious dose for secondary stroke prevention., (© 2023 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

The SARS-CoV-2 virus, which causes Coronavirus-19 infection (COVID-19), frequently elicits the development of depressed immunity, therefore, opportunistic infections. Opportunistic organisms are commonly present in the human body without causing critical illness. However, they can also lead to pathologic illness when a person is immunocompromised. Aspergillosis is among the many opportunistic infections. Even though this infection primarily involves the respiratory system and is less likely to be found in the gastrointestinal tract, we report a case of a COVID-19 individual that developed massive gastrointestinal bleeding whose condition deteriorated, and the pathological examination revealed gastric aspergillosis. Although not common, gastric aspergillosis should be considered while treating patients with COVID-19 who present gastrointestinal symptoms., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Hinojosa et al.)

Monkeypox virus (MPXV) continues to pose severe threats to global public health, especially in non-endemic areas. Like all other regions, Africa faces potential public health crises due to the ongoing COVID-19 pandemic and other infectious disease outbreaks (such as Lassa fever and malaria) that have devastated the region and overwhelmed the healthcare systems. Owing to the recent surge in the MPXV and other infections, the COVID-19-control efforts could deteriorate and further worsen. This study discusses the potential emergencies of MPXV transmission during the current COVID-19 pandemic. We hypothesize some of the underlying drivers that possibly resulted in an increase in rodent-to-human interaction, such as the COVID-19 pandemic's impact and other human behavioral or environmental factors. Furthermore, we estimate the MPXV time-varying effective reproduction number (Rt) based on case notification in Nigeria. We find that Rt reached a peak in 2022 with a mean of 1.924 (95% CrI: 1.455, 2.485) and a median of 1.921 (95% CrI: 1.450, 2.482). We argue that the real-time monitoring of Rt is practical and can give public health authorities crucial data for circumstantial awareness and strategy recalibration. We also emphasize the need to improve awareness programs and the provision of adequate health care resources to suppress the outbreaks. These could also help to increase the reporting rate and, in turn, prevent large community transmission of the MPXV in Nigeria and beyond.

Purpose: In Afghanistan, research work is still in its infancy and there is no national level tumor registry at the moment in the country that could elaborate the histopathological features of ovarian tumors in the country. The current study was conducted with the aim to describe pathological characteristics of ovarian tumors diagnosed at tertiary level in Afghanistan., Patients and Methods: A descriptive cross-sectional study was conducted, including 198 cases diagnosed with ovarian tumors, that were consecutively included in the study from July 2017 to August 2020. All the cases were diagnosed at the Department of Pathology, French Medical Institute for Mothers and Children, Kabul, Afghanistan, that receives biopsy samples from all of the tertiary care institutions in Kabul., Results: In the current study, majority of the ovarian tumors were benign and presented with nonspecific symptoms. The mean age at diagnosis was 34.4 (SD ±13.4). Benign tumors comprised 81.8%, borderline 1.5% and malignant 16.7% of the cases. Majority of the diagnosed tumors were from surface epithelium in origin, followed by germ cell tumors, sex cord stromal tumors, and a single metastatic tumor. The most common benign neoplasm was mature cystic teratoma, followed by benign serous cystadenoma. Considering the malignant tumors, serous cystadenocarcinoma and adult granulosa cell tumors were predominant, followed by endometrioid adenocarcinoma and mucinous cystadenocarcinoma. More than half of the ovarian tumors occurred between 21 and 40 years of age., Conclusion: In the current study, the proportion of malignant ovarian neoplasms was significantly less than benign lesions. Although, many of the pathological features related to ovarian neoplasms were similar to the features demonstrated in other regions of the world, there were important findings that were exclusively noted in the cases diagnosed in Afghanistan., Competing Interests: All the authors report no conflicts of interest in this research work., (© 2022 Ibrahimkhil et al.)

Background: Worldwide, esophageal cancer (EC) is a common cancer in term of incidence and mortality and is the 4th common cancer in Afghanistan. Current study aimed to evaluate the profile of risk factors for EC among patients diagnosed at tertiary level in Afghanistan., Methodology: A descriptive cross-sectional study was carried out between January 2019 up to February 2021 including all esophageal cancers diagnosed at pathology department of French Medical Institute for Mothers and Children, Afghanistan., Result: 240 diagnosed cases were analyzed, in which 59.40% of squamous cell carcinoma and 41.07% Adenocarcinoma. Both histopathological type of were predominantly diagnosed in males. The majority of the patients were residents of rural areas. More than 80% of the patients were illiterate with only less than 2% completing higher education. Majority of the patients were laborers and farmers while less than 10% were employed. According to income assessment, more than 80% were from low-income household, the rest from middle-income and none from high-income family. Oral snuff consumption was noted in 33.9% of squamous cell carcinoma patients and 40% adenocarcinoma patients whereas, family history of esophageal cancer was observed in 37.8% and 36.7% in both types of carcinomas, respectively. More than 60% of both types of carcinomas patients were hot tea drinkers., Conclusion: Current study demonstrated that most patients diagnosed with esophageal cancers were male, uneducated, belongs to low-income groups, lives in rural areas. These findings suggest distribution of esophageal cancer in specific socioeconomic groups, clearly demonstrating the need further analytical study., (© 2022. The Author(s).)

Background: The COVID-19 pandemic poses serious threats to public health globally, and the emerging mutations in SARS-CoV-2 genomes has become one of the major challenges of disease control. In the second epidemic wave in Nigeria, the roles of co-circulating SARS-CoV-2 Alpha (ie, B.1.1.7) and Eta (ie, B.1.525) variants in contributing to the epidemiological outcomes were of public health concerns for investigation., Methods: We developed a mathematical model to capture the transmission dynamics of different types of strains in Nigeria. By fitting to the national-wide COVID-19 surveillance data, the transmission advantages of SARS-CoV-2 variants were estimated by likelihood-based inference framework., Results: The reproduction numbers were estimated to decrease steadily from 1.5 to 0.8 in the second epidemic wave. In December 2020, when both Alpha and Eta variants were at low prevalent levels, their transmission advantages (against the wild type) were estimated at 1.51 (95% credible intervals (CrI) = 1.48, 1.54), and 1.56 (95% CrI = 1.54, 1.59), respectively. In January 2021, when the original variants almost vanished, we estimated a weak but significant transmission advantage of Eta against Alpha variants with 1.14 (95% CrI = 1.11, 1.16)., Conclusions: Our findings suggested evidence of the transmission advantages for both Alpha and Eta variants, of which Eta appeared slightly more infectious than Alpha. We highlighted the critical importance of COVID-19 control measures in mitigating the outbreak size and relaxing the burdens to health care systems in Nigeria., Competing Interests: Competing interest: MHW is a shareholder of Beth Bioinformatics Co., Ltd The authors have all completed the ICMJE Declaration of Interest form (available upon request from the corresponding authors), and declare no further competing interests., (Copyright © 2021 by the Journal of Global Health. All rights reserved.)

A mathematical model is designed to assess the impact of some interventional strategies for curtailing the burden of snakebite envenoming in a community. The model is fitted with real data set. Numerical simulations have shown that public health awareness of the susceptible individuals on snakebite preventive measures could reduce the number of envenoming and prevent deaths and disabilities in the population. The simulations further revealed that if at least fifty percent of snakebite envenoming patients receive early treatment with antivenom a substantial number of deaths will be averted. Furthermore, it is shown using optimal control that combining public health awareness and antivenom treatment averts the highest number of snakebite induced deaths and disability adjusted life years in the study area. To choose the best strategy amidst limited resources in the study area, cost effectiveness analysis in terms of incremental cost effectiveness ratio is performed. It has been established that the control efforts of combining public health awareness of the susceptible individuals and antivenom treatment for victims of snakebite envenoming is the most cost effective strategy. Approximately the sum of US$72,548 is needed to avert 117 deaths or 2,739 disability adjusted life years that are recorded within 21 months in the study area. Thus, the combination of these two control strategies is recommended., Competing Interests: The authors have declared that no competing interests exist.

Recurrent ischemic priapism is a common complication of sickle cell disease (SCD). We assessed the burden, characteristics, and types of priapism, including sexual dysfunction, in a cohort of men with and those without SCD, to test the hypothesis that sexual dysfunction is more prevalent in men with SCD. In Kano, Nigeria, we conducted a comparative cross-sectional survey that included 500 and 250 men 18 to 40 years of age, with and without SCD, respectively. The survey used the Priapism Questionnaire and the International Index of Erectile Function for sexual function assessment. All eligible participants approached for the study gave informed consent and were enrolled. Stuttering and major priapism were defined based on the average duration of priapism experiences that lasted ≤4 and >4 hours, respectively. The prevalence of priapism was significantly higher in men with SCD than in those without it (32.6% vs 2%; P < .001). Stuttering priapism accounted for 73.6% of the priapism episodes in men with SCD. Nearly 50% of the participants with SCD-related priapism had never sought medical attention for this complication. The majority of the men with SCD-related priapism used exercise as a coping mechanism. Priapism affected the self-image of the men with SCD, causing sadness, embarrassment, and fear. The percentage of the men with SCD who had erectile dysfunction was more than twofold higher than that of those without SCD who had erectile dysfunction (P = .01). The men with SCD had a higher prevalence of priapism and sexual dysfunction than the men without SCD., (© 2020 by The American Society of Hematology.)

Zoonotic visceral leishmaniasis (ZVL), caused by the protozoan parasite Leishmania infantum and transmitted to humans and reservoir hosts by female sandflies, is endemic in many parts of the world (notably in Africa, Asia and the Mediterranean). This study presents a new mathematical model for assessing the transmission dynamics of ZVL in human and non-human animal reservoir populations. The model undergoes the usual phenomenon of backward bifurcation exhibited by similar vector-borne disease transmission models. In the absence of such phenomenon (which is shown to arise due to the disease-induced mortality in the host populations), the nontrivial disease-free equilibrium of the model is shown to be globally-asymptotically stable when the associated reproduction number of the model is less than unity. Using case and demographic data relevant to ZVL dynamics in Arac̣atuba municipality of Brazil, it is shown, for the default case when systemic insecticide-based drugs are not used to treat infected reservoir hosts, that the associated reproduction number of the model ( ℛ 0 ) ranges from 0.3 to 1.4, with a mean of ℛ 0 = 0.85 . Furthermore, when the effect of such drug treatment is explicitly incorporated in the model (i.e., accounting for the additional larval and sandfly mortality, following feeding on the treated reservoirs), the range of ℛ 0 decreases to ℛ 0 ∈ [ 0.1 , 0.6 ] , with a mean of ℛ 0 = 0.35 (this significantly increases the prospect of the effective control or elimination of the disease). Thus, ZVL transmission models (in communities where such treatment strategy is implemented) that do not explicitly incorporate the effect of such treatment may be over-estimating the disease burden (as measured in terms of ℛ 0 ) in the community. It is shown that ℛ 0 is more sensitive to increases in sandfly lifespan than that of the animal reservoir (so, a strategy that focuses on reducing sandflies, rather than the animal reservoir (e.g., via culling), may be more effective in reducing ZVL burden in the community). Further sensitivity analysis of the model ranks the sandfly removal rate (by natural death or by feeding from insecticide-treated reservoir hosts), the biting rate of sandflies on the reservoir hosts and the progression rate of exposed reservoirs to active ZVL as the three parameters with the most effect on the disease dynamics or burden (as measured in terms of the reproduction number ℛ 0 ). Hence, this study identifies the key parameters that play a key role on the disease dynamics, and thereby contributing in the design of effective control strategies (that target the identified parameters).