Study on the optimal incident proton energy of ^(7)Li(p,n)^(7)Be neutron source for boron neutron capture therapy

Boron neutron capture therapy(BNCT)is recognized as a precise binary targeted radiotherapy technique that effectively eliminates tumors through the^(10)B(n,α)^(7)Li nuclear reaction.Among various neutron sources,accelerator-based sources have emerged as particularly promising for BNCT applications.The^(7)Li(p,n)^(7)Be reaction is highly regarded as a potential neutron source for BNCT,owing to its low threshold energy for the reaction,significant neutron yield,appropriate average neutron energy,and additional benefits.This study utilized Monte Carlo simulations to model the physical interactions within a lithium target subjected to proton bombardment,including neutron moderation by an MgF_(2)moderator and subsequent BNCT dose analysis using a Snyder head phantom.The study focused on calculating the yields of epithermal neutrons for various incident proton energies,finding an optimal energy at 2.7 MeV.Furthermore,the Snyder head phantom was employed in dose simulations to validate the effectiveness of this specific incident energy when utilizing a^(7)Li(p,n)^(7)Be neutron source for BNCT purposes.

Current Status of Congenital Toxoplasmosis in Brazzaville, Republic of the Congo

Toxoplasmosis is a parasitic infection caused by Toxoplasma gondii, which is transmitted by contact with animals carrying the parasite, or by eating contaminated food such as undercooked meat or raw fruit and vegetables. Toxoplasmosis is often benign, but can be serious in pregnant women. In order to assess the prevalence of congenital toxoplasmosis in Brazzaville, Republic of Congo, 464 women aged between 16 and 42 were surveyed in 3 health facilities, including one public hospital (Blanche Gomez) and two private medical centers (OCH medical and ultrasound practice and Luiz laboratory). A total of 1868 samples were taken and analyzed using the ELFA method on mini vidas, an enzyme-linked immunosorbent assay for fluorescence detection. The results showed that out of 1392 samples obtained from 464 pregnant women, 693 samples from 231 pregnant women were positive, i.e. a frequency of 49.78%. Analysis of the immunological profile showed 48.70% IgG and 1.07% IgG associated with IgM. The different frequencies varied from one health facility to another: 53.96% at Blanche Gomez Hospital, 53.76% at Luiz Laboratory and 31% at OCH. Seroprevalence by age group showed 57.14% in pregnant women aged 16 to 25, 52.77% in pregnant women aged 26 to 35 and 21.62% in pregnant women aged 36 to 42. A frequency of 52.65% was observed in pregnant women in contact with soil and 49.78% in pregnant women consuming vegetables, while 66.66% of women in contact with cats were positive for toxoplasmosis. IgG avidity assays showed a frequency of 74% for high avidity and 3.75% for low avidity. This study enabled us to diagnose 9 cases of seroconversion, including 6 cases of congenital toxoplasmosis. Among the 6 cases, 4 children showed toxoplasmosis with sub-clinical signs of IgG persistence at one year of age, including one with thrombocytopenia associated with jaundice and 2 others with hepatomegaly associated with hypertransaminase and hyperbilirubinemia. The maternal-fetal transmission rate was 66.66%, with an incidence of congenital toxoplasmosis of 1.29 per 464 births.In conclusion, the results of this study show the impact of toxoplasmosis on public health, and demonstrate the importance of quarterly pregnancy monitoring and compliance with hygienic and dietary measures, which are very important for prevention, early detection and management of contaminated pregnant women during prenatal monitoring, thereby reducing the consequences for newborns.

Contribution to the Study of the Incidence of Post-Streptococcal Complications in Republic Central African Republic from 2015 to 2018

Introduction: Acute rheumatic fever (AAR) is a non-suppurative complication of late infection by group A. Infections due to streptococci remain a public health problem in the Central African Republic. The present study aims to determine the incidence rate of AAR cases and its complications. Methodology: This was a retrospective and analytical study over a period of 4 years (from January 2015 to December 2018) at the National Laboratory of Clinical Biology and Public Health (LNBCSP) in Bangui. It focused on samples concerning the diagnosis of AAR and patient files seen in consultation in the capital’s reference health establishments. Laboratory registers and patient consultation files were used to collect data. They were entered into Excel 2010 to be analyzed with Epi Info 7. A univariate analysis by logistic regression, Ficher’s exact test, and chi2 at the 5% threshold (p Results: We analyzed 94 cases meeting Jones’s criteria. The ages of the patients ranged from 18 to 85 years (mean age 52 years and mode 45 years). The incidence rate of AAR for the female sex was higher than that of the male sex during the study period (p > 0.05). It went from 166.6 in 2015 to 200 in 2016 and 2018 cases of AAR per 1000 people per year. The average incidence rate was 296.18 cases of AAR per 1000 people per year. The average incidence rate was 223.5 cases of AAR per 1000 people per year for joint damage. Joint damage represented 80.85% (RR = 0.62;Chi2 = 4.88;95% CI [0.39-0.97];p Conclusion: The study allowed data on the impact rate and complications of the AAR in Bangui. Special attention to data management will help produce a complete result on the problem. Joint complications predominated. Sustaining an effective surveillance system and preventing infection would help reduce the risk of AAR occurrence.

Recent trends in the epidemiology and clinical outcomes of inflammatory bowel disease in South Korea,2010-2018

BACKGROUND Inflammatory bowel disease(IBD)was previously regarded as a Western disease;however,its incidence is increasing in the East.The epidemiology of IBD in Asia differs significantly from the patterns in the West.AIM To comprehensively investigate the epidemiology of IBD in South Korea,inclu-ding its incidence,prevalence,medication trends,and outcomes.METHODS We analyzed claims data from the Health Insurance Review and Assessment Service and Rare and Intractable Diseases(RIDs),operated by the National Health Insurance Service of South Korea.Patients with IBD were identified based on the International Classification of Diseases,Tenth Revision,and RID diagnostic codes for Crohn’s disease(CD)and ulcerative colitis(UC)from 2010 to 2018.RESULTS In total,14498 and 31409 patients were newly diagnosed with CD and UC,respectively,between 2010 and 2018.The annual average incidence of CD was 3.11 cases per 105 person-years,and that of UC was 6.74 cases per 10^(5) person-years.Since 2014,the incidence rate of CD has been stable,while that of UC has steadily increased,shifting the peak age group from 50-year-olds in 2010 to 20-year-olds in 2018.The CD and UC prevalence increased consistently over the study period;the use of 5-aminosali-cylates and corticosteroids gradually decreased,while that of immunomodulators and biologics steadily increased in both CD and UC.The clinical outcomes of IBD,such as hospitalization and surgery,decreased during the study period.CONCLUSION The CD incidence has been stable since 2014,but that of UC has increased with a shift to a younger age at peak incidence between 2010 and 2018.IBD clinical outcomes improved over time,with increased use of immunomodu-lators and biologics.

Influence of Temperature and Humidity on the Incidence of Pulmonary Tuberculosis in Hainan,China,2004-2018

According to the World Health Organization’s Global Tuberculosis Report 2023,there were 10.6 million cases of tuberculosis(TB)worldwide in 2022,an increase of 2.8%over 2021,and 1.3 million people had already died of the disease.The report also indicated that approximately 748,000 new cases occurred in China in 2022,accounting for 7.1%of the global total,with an incidence of 52/100,000.

GNSS array receiver faced with overloaded interferences:anti-jamming performance and the incident directions of interferences

Anti-jamming solutions based on antenna arrays enhance the anti-jamming ability and the robustness of global navigation satellite system(GNSS)receiver remarkably.However,the performance of the receiver will deteriorate significantly in the overloaded interferences scenario.We define the overloaded interferences scenario as where the number of interferences is more than or equal to the number of antenna arrays elements.In this paper,the effect mechanism of interferences with different incident directions is found by studying the anti-jamming performance of the adaptive space filter.The theoretical analysis and conclusions,which are first validated through numerical examples,reveal the relationships between the optimal weight vector and the eigenvectors of the input signal autocorrelation matrix,the relationships between the interference cancellation ratio(ICR),the signal to interference and noise power ratio(SINR)of the adaptive space filter output and the number of interferences,the eigenvalues of the input signal autocorrelation matrix.In addition,two simulation experiments are utilized to further corroborate the theoretical findings through soft anti-jamming receiver.The simulation results match well with the theoretical analysis results,thus validating the effect mechanism of overloaded interferences.The simulation results show that,for a four elements circular array,the performance difference is up to 19 dB with different incident directions of interferences.Anti-jamming performance evaluation and jamming deployment optimization can obtain more accurate and efficient results by using the conclusions.

Incidence and Management of Early Postoperative Hypoxemia after Abdominal Surgery at Teaching Hospital

Background: Oxygen saturation refers to the quantity of oxygenated hemoglobin in the blood, that is to say the level of oxygen measurable in the red blood cells when they have passed through the lungs. The aim of this study was to describe the management of early postoperative hypoxemia after abdominal surgery at the Yaounde General Hospital (YGH). Method: This is a quantitative, observational study, with a descriptive aim, which took place in the anesthesiology department of the YGH, over a period of 2 months from August 1st to October 1st, 2023. The study included all the patients ≥18 years, of both sexes who had abdominal surgery under general anesthesia and were willing to participate during the time of data collection. The variables studied were the sociodemographic and clinical characteristics, risk factors for oxygen desaturation, postoperative variations in SPO2 and therapeutic tools. Results: We collected 30 patients among whom 11 presented with early postoperative hypoxemia i.e. a frequency of 36.7%. The age of the patients ranged from 18 to 63 years and the mean was 42.47 ± 13.5 years on average. The sex ratio was 0.5. Hysterectomy was the most commonly performed surgery (23.3%). The most common comorbidity was high blood pressure (30%). Half of the patients had midline incision. Supra-umbilical surgery predominated (56.7%), intraoperative blood loss ≥500 ml in 46.7% of cases. Upper abdominal surgery with, subcostal incision and blood loss ≥500 ml are statistically significant risk factors for the occurrence of early postoperative hypoxemia (P Conclusion: Hypoxemia is the result of impaired respiratory function favored by the conditions encountered during the early postoperative period.

Incidence and Survivability of Acute Lymphocytic Leukemia Patients in the United States: Analysis of SEER Data Set from 2000-2019

The main goal of this research is to assess the impact of race, age at diagnosis, sex, and phenotype on the incidence and survivability of acute lymphocytic leukemia (ALL) among patients in the United States. By taking these factors into account, the study aims to explore how existing cancer registry data can aid in the early detection and effective treatment of ALL in patients. Our hypothesis was that statistically significant correlations exist between race, age at which patients were diagnosed, sex, and phenotype of the ALL patients, and their rate of incidence and survivability data were evaluated using SEER*Stat statistical software from National Cancer Institute. Analysis of the incidence data revealed that a higher prevalence of ALL was among the Caucasian population. The majority of ALL cases (59%) occurred in patients aged between 0 to 19 years at the time of diagnosis, and 56% of the affected individuals were male. The B-cell phenotype was predominantly associated with ALL cases (73%). When analyzing survivability data, it was observed that the 5-year survival rates slightly exceeded the 10-year survival rates for the respective demographics. Survivability rates of African Americans patients were the lowest compared to Caucasian, Asian, Pacific Islanders, Alaskan Native, Native Americans and others. Survivability rates progressively decreased for older patients. Moreover, this study investigated the typical treatment methods applied to ALL patients, mainly comprising chemotherapy, with occasional supplementation of radiation therapy as required. The study demonstrated the considerable efficacy of chemotherapy in enhancing patients’ chances of survival, while those who remained untreated faced a less favorable prognosis from the disease. Although a significant amount of data and information exists, this study can help doctors in the future by diagnosing patients with certain characteristics. It will further assist the health care professionals in screening potential patients and early detection of cases. This could also save the lives of elderly patients who have a higher mortality rate from this disease.

Incidence,Risk Factors,and Prognosis of Patients with Hepatocellular Carcinoma and Brain Metastases

Objective Brain metastases significantly impact the clinical course of patients with hepatocellular carcinoma(HCC).This study aimed to examine the age-related incidence,demographics,and survival of patients with HCC and brain metastases.Methods Data of HCC patients from 2010 to 2015 in the Surveillance,Epidemiology,and End Results(SEER)Registry were screened for the presence of brain metastases.They were stratified by age and ethnicity.Multivariable logistic and Cox regression analyses were used to identify factors associated with brain metastases and those with overall survival(OS)and liver cancer-specific survival(CSS),respectively.Results A total of 141 HCC patients presenting with brain metastases were identified,accounting for 0.35% of all HCC patients and 2.37% of patients with metastatic disease.Among all HCC patients,the incidence rate was the highest among patients aged 30-49 years old(0.47%).Ethnicity was not associated with the presence of brain metastases at the time of HCC diagnosis.However,African-American patients presented with a significantly lower disease-specific survival[median time:1 month;interquartile range(IQR):0-3.0 months].Initial lung or bone metastasis was independently associated with an increased risk of the presence of brain metastases[odds ratio(OR):12.62,95% confidence interval(CI):8.40-18.97]but was not associated with a worse OS or CSS among those with brain metastases.Conclusion This study identified the age-related incidence and risk factors of brain metastases in HCC patients.These results may contribute to the consideration of brain screening among patients with initial metastatic HCC with lung or bone metastases,and influence the counseling of this patient population regarding their prognosis.

Esophageal cancer global burden profiles, trends, and contributors

Objective:This study aimed to provide a comprehensive overview of the global burden of esophageal cancer(EC)and determine the temporal trends and factors influencing changes in the global burden.Methods:The latest incidence and mortality data for EC worldwide were obtained from GLOBALCAN 2022.The mortality and disability-adjusted life years(DALYs)rates for EC from 1990±2019 were sourced from the 2019 Global Burden of Diseases.Trends in EC mortality and DALYs attributable to 11 risk factors or clusters of risk were analyzed using the joinpoint regression model.The trends in age-related EC burden were assessed using a decomposition approach.Results:An estimated 511,054 new cases of EC were diagnosed in 2022 with 445,391 deaths worldwide.Approximately 75%of cases and deaths occurred in Asia.Nearly 50%of global EC deaths and DALYs were attributed to tobacco use in men in 2019,while 20%were attributed to high body mass index(BMI)in women.From 1990±2019,EC deaths and DALYs attributable to almost all risk factors had declining trends,while EC deaths and DALYs attributed to high BMI in men had upward trends.The age-related EC burden exhibited an upward trend driven by population growth and aging,which contributed to 307.4 thousand deaths and 7.2 million DALYs due to EC.Conclusions:The EC burden remains substantial worldwide.Effective tobacco and obesity control measures are critical for addressing the risk-attributable burden of EC.Population growth and aging pose challenges for EC prevention and control efforts.

Characteristics of the electromagnetic wave propagation in magnetized plasma sheath and practical method for blackout mitigation

“Magnetic window”is considered as an effective method to solve the communication blackout issue.COMSOL software package based on the finite element method is utilized to simulate the propagation of right-handed circularly polarized wave in the magnetized plasma sheath.We assume a double Gaussian model of electron density and an exponential attenuation model of magnetic field.The propagation characteristics of right-handed circularly polarized wave are analyzed by the observation of the reflected,transmitted and loss coefficient.The numerical results show that the propagation of right-handed circularly polarized wave in the magnetized plasma sheath varies for different incident angles,collision frequencies,non-uniform magnetic fields and non-uniform plasma densities.We notice that reducing the wave frequency can meet the propagation conditions of whistle mode in the weak magnetized plasma sheath.And the transmittance of whistle mode is less affected by the variation of the electron density and the collision frequency.It can be used as a communication window.

Survey on Blood Transfusion Practices among Medical and Paramedical Staff in the Pediatric Unit of the Mohammed VI University Hospital in Marrakesh, Morocco

Blood transfusion is a complex activity, involving many actors. As a high-risk activity, it necessitates the implementation of specific methods for effective control. The safety of blood transfusion is significantly influenced by the beliefs of healthcare workers and organizational factors, constituting two major considerations. We conducted a cross-sectional, descriptive, and analytical survey to examine the knowledge and practices related to transfusion among the medical and paramedical staff at the Pediatric Department (Mother-Child) of CHU Mohammed VI from September 1, 2022, to December 31, 2022. Among the 135 staff members interviewed, only 41% had received training in blood transfusion. A majority (65.2%) of the staff noted that a mismatch in cross-matching led to transfusion complications. Two-thirds (66.7%) identified chills as the primary clinical sign of potential accidents. Regarding elements to monitor during a reaction, hemolysis (78.5%) and temperature (76.3%) were most commonly mentioned. Surprisingly, more than half (53.3%) of the personnel interviewed did not conduct post-transfusion monitoring. This survey highlighted significant deficiencies in knowledge and practices related to transfusion. To address these issues, we recommend implementing guidelines and providing tailored training for the staff, aiming to rectify these deficiencies and enhance overall practices.

Incidence and Management of Occupational Blood Exposure (OBE) among Medical Students at the University of Bangui

Introduction: Like healthcare workers, medical students are also exposed to a risk of accidental contamination during their hospital internships. However, they do not benefit from prevention services in the same way as workers in this sector, although they actively participate in the routine care provided to patients in the various hospital departments. The objective of our study is to determine the incidence of these accidents and their medical and administrative management among these victims (medical students) not classified in the category of workers. Materials and Method: This was a cross-sectional study carried out over three months from January 15 to March 14, 2023. The study population consisted of all medical students at the Faculty of Health Sciences at the University of Bangui. Regularly enrolled students from 2nd to 7th year, on placement in hospitals in the Central African Republic and who gave their informed consent were included. Data were collected through a self-administered questionnaire. Results: A cross-sectional study was carried out among medical students concerning the incidence and management of accidents involving exposure to blood in the Central African Republic. Of the 254 students included, three (9%) had already been correctly vaccinated against the viral hepatitis B virus, 198 (77.9%) reported still having access to personal protective equipment, 133 students (52.4%) reported being victims of OBE in the past 12 months. The main types of OBE were stings (62%), followed by liquid splashes (32%) and cuts (6%). Among the 133 victims, 92.9% carried out immediate hand disinfection or abundant eye washing, 41.9% obtained the serology of the source patient and 37% reported the accident to their supervisor. Conclusion: It is important that students benefit from better prevention and management of these accidents.

Corrective Effect of the Angle of Incidence of the Magnetic Field Intensity on the Performance (Series and Shunt Resistances) of a Bifacial Silicon Solar Cell

This article presents a three-dimensional analysis of the impact of the angle of incidence of the magnetic field intensity on the electrical performance (series resistance, shunt resistance) of a bifacial polycrystalline silicon solar cell. The cell is illuminated simultaneously from both sides. The continuity equation for the excess minority carriers is solved at the emitter and at the depth of the base respectively. The analytical expressions for photocurrent density, photovoltage, series resistance and shunt resistance were deduced. Using these expressions, the values of the series and shunt resistances were extracted for different values of the angle of incidence of the magnetic field intensity. The study shows that as the angle of incidence increases, the slopes of the minority carrier density for the two modes of operation of the solar cell decrease. This is explained by a drop in the accumulation of carriers in the area close to the junction due to the fact that the Lorentz force is unable to drive the carriers towards the lateral surfaces due to the weak action of the magnetic field, which tends to cancel out as the incidence angle increases, and consequently a drop in the open circuit photovoltage. This, in turn, reduces the Lorentz force. These results predict that the p-n junction of the solar cell will not heat up. The study also showed a decrease in series resistance as the incidence angle of the magnetic field intensity increased from 0 rad to π/2 rad and an increase in shunt resistance as the incidence angle increased. His behaviour of the electrical parameters when the angle of incidence of the field from 0 rad to π/2 rad shows that the decreasing magnetic field vector tends to be collinear with the electron trajectory. This allows them to cross the junction and participate in the external current. The best orientation for the Lorentz force is zero, in which case the carriers can move easily towards the junction.

An improved algorithm based on equivalent sound velocity profile method at large incident angle

With the development of ultra-wide coverage technology,multibeam echo-sounder(MBES)system has put forward higher requirements for localization accuracy and computational efficiency of ray tracing method.The classical equivalent sound speed profile(ESSP)method replaces the measured sound velocity profile(SVP)with a simple constant gradient SVP,reducing the computational workload of beam positioning.However,in deep-sea environment,the depth measurement error of this method rapidly increases from the central beam to the edge beam.By analyzing the positioning error of the ESSP method at edge beam,it is discovered that the positioning error increases monotonically with the incident angle,and the relationship between them could be expressed by polynomial function.Therefore,an error correction algorithm based on polynomial fitting is obtained.The simulation experiment conducted on an inclined seafloor shows that the proposed algorithm exhibits comparable efficiency to the original ESSP method,while significantly improving bathymetry accuracy by nearly eight times in the edge beam.

Hepatocellular carcinoma national burden across different geographical regions in the United States between 2001 and 2020

BACKGROUND While prior data showed an increasing incidence of hepatocellular carcinoma(HCC)in the United States,there are limited comprehensive and comparative data on the geographical variations of HCC trends in different demographicspecific populations.AIM To evaluate sex and age-specific incidence rates and time trends in different geographical regions in the United States.METHODS Age-adjusted HCC incidence rates were collected from the United States Cancer Statistics(USCS)database which covers approximately 98%of the population in the United States.HCC rates were stratified by sex,age,and geographical region.annual percentage change(APC)and average APC(AAPC)were estimated using Joinpoint Regression.A pairwise comparison was conducted between sex-specific trends.RESULTS There were 467344 patients diagnosed with HCC in the United States in the USCS database between 2001 and 2020.The rates and trends varied by geographical region.When looking at the West region(115336 patients),incidence rates of HCC were overall increasing and also increasing in older adults.However,when evaluating younger adults,HCC incidence rates decreased in men but not in women with a sex-specific absolute AAPC-difference of 2.15(P=0.005).When evaluating the Midwest region(84612 patients),similar results were seen.While incidence rates were increasing in the overall population and in older adults as well,they were decreasing in younger men but not in women with a sex-specific absolute AAPC-difference of 1.61(P<0.001).For the Northeast region(87259 patients),the analysis showed similar results with decreasing HCC incidence rates in younger men but not counterpart women(Sex-specific AAPC-difference=3.26,P<0.001).Lastly,when evaluating the south(180137 patients),the results were also decreasing in younger men but not in women(Sex-specific AAPC-difference=2.55,P<0.001).CONCLUSION Nationwide analysis covering around 98%of the United States population shows an increasing incidence of HCC across all geographical regions,most notably in the South.While younger men experienced decreasing HCC incidence,younger women had a stable trend and this was noted across all regions as well.Our study offers insight into the epidemiology of HCC in different demographic groups across various United States geographical regions.While the reasons contributing to our findings are unclear,they can be related to sex and regional disparities in healthcare access and utilization.Future research is warranted to characterize the temporal change in HCC risk factors across different United States regions.

Stability of a Delayed Stochastic Epidemic COVID-19 Model with Vaccination and with Differential Susceptibility

In this paper, we treat the spread of COVID-19 using a delayed stochastic SVIRS (Susceptible, Infected, Recovered, Susceptible) epidemic model with a general incidence rate and differential susceptibility. We start with a deterministic model, then add random perturbations on the contact rate using white noise to obtain a stochastic model. We first show that the delayed stochastic differential equation that describes the model has a unique global positive solution for any positive initial value. Under the condition R0 ≤ 1, we prove the almost sure asymptotic stability of the disease-free equilibrium of the model.

Analysis of Trends of Cancer Epidemiology in Two Provinces of the Western and Eastern China

In this paper, the literature on the incidence and death of malignant tumors in the Chongqing and Jiangsu provinces from 2014-2016 was collected through a literature review. The overall incidence, mortality, tumor spectrum, and possible risk factors of malignant tumor incidence and death in the Chongqing and Jiangsu provinces were compared and analyzed. This aims to provide references and suggestions for the prevention and control of malignant tumors in China.

Complications Related to the Insertion Technique of Jadelle® Contraceptive Implants

Introduction: Contraceptive implants are one of the most effective methods of birth spacing. Jadelle® implants consist of two strands that are easy to insert and remove. Although their effectiveness is no longer in question, their use (insertion) requires a surgical procedure with the corollary possibility of complications. These are mainly insertions that are too deep (in the arm muscle), vascular and nerve damage. Material and Methods: Our study focused on complications related to implant insertion. It was a descriptive and retrospective study over thirty-four months, from October 2016 to July 2019, and concerned all patients seen in consultation and who presented a complication related to the insertion of contraceptive implants in the Department of Gynecology and Obstetrics of the National Hospital of Pikine. Results: We collected nine complications managed at the Gynecology and Obstetrics Department of the Centre Hospitalier National de Pikine from 2016 to 2019. These were insertions that were too deep with sometimes nerve damage, infection or incident during anesthesia. The operative procedures were based on the type of complication. Conclusion: Although Jadelle® has the advantage of having only 2 rods compared to its predecessor Norplant®, its use is also conditioned by insertion and removal procedures which may experience complications.

Study on incidence of lamb morbidity and mortality and associated risk factors in the mixed crop‑livestock production system of Gewata District, Kaffa zone, southwestern Ethiopia

Lamb morbidity and mortality cause significant loss in a smallholder production system. A longitudinal prospectivesurvey was conducted on 408 randomly selected farmers located in six purposefully selected kebeles in Gewataworeda from June 2020 to July 2021 to determine the incidence of morbidity and mortality in lambs and to identifyrisk factors. For this purpose, 408 lambs from the Gewata district’s mixed crop-livestock production system wereexamined every day from birth to three months of age. The data was analyzed using the Kaplan-Meier (K-M) method,the log-rank test, and Cox proportional hazards regression. Results showed that the cumulative incidence of allcauseof morbidity and mortality at the end of three month was 12.86% (95% CI: 10.26–16.13%), and 6.86% (95% CI:5.03–9.35%), respectively. Diarrhea was the leading cause of morbidity and mortality, accounting for 49.33 and 50%morbidity and mortality, respectively. Pneumonia was the second most frequent cause of morbidity and death. In theK-M hazard analysis, the greatest risk of lamb morbidity and mortality was observed during the first month of life, andthen the risk decreased significantly as the lamb grew. Of the 17 potential risk factors studied, the multivariable Coxproportional hazards regression model showed that lamb sex, birth weight, umbilical care, time and method of colostrumfeeding were the five predictors that were significantly associated with a higher risk of morbidity, whereas birthweight, lambing difficulty, dams’ parity, method and time of colostrum feeding were the five predictors that weresignificantly associated with a higher risk of mortality. Moreover, a higher risk of morbidity was observed in lambswith methods of colostrum feeding after birth (HR = 3.158;p = 0.000) and with variations in birth weight (HR = 1.418;p = 0.003). Similarly, the mortality risk was 4.926 (p = 0.047), 4.023 (p = 0.012), and 3.206 (p = 0.000) times higher inlambs with lambing difficulties, at the time of colostrum feeding, and by the method of colostrum feeding, respectively.According to this research, lamb morbidity and mortality rates in the study area are significantly high whichhas a great impact on the replacement stock and production. Hence, awareness should be created among farmersconcerning improved lamb management practices.