The impact of leptospirosis in northern Tanzania

Leptospirosis is an underappreciated cause of human illness and livestock production loss in the tropics. Our understanding of the burden of disease, reservoirs and sources of human infection, and the performance of point-of-care diagnostic tests is limited in African countries. To fill data gaps, we recruited patients presenting with fever to two hospitals in Moshi, northern Tanzania, during 2012-2014 and at Endulen Hospital during 2016-17. We tested participants for leptospirosis using microscopic agglutination testing (MAT), Leptospira culture, and in a subset, polymerase chain reaction (PCR) and IgM point-of-care tests and evaluated test accuracy. We conducted a case-control study to identify risk factors for acute leptospirosis and conducted a survey of community livestock owners across northern Tanzania. We estimated leptospirosis incidence from the prevalence in Moshi Rural and Moshi Urban Districts by using multipliers derived from a health-care utilisation survey and calculated disability adjusted life years (DALYs). We compared MAT serogroup reactivity and Leptospira species detected in people with those detected in animals. To assess potential animals hosts of Leptospira serogroups and species we conducted a systematic review of all typed isolations and PCR detections of Leptospira from animals. We estimated the incidence of leptospirosis in several districts in northern Tanzania using a model that predicted an individual’s probability of leptospirosis based on their risk factors and the presence of recent fever. We estimated the annual leptospirosis incidence in Moshi Rural and Moshi Urban Districts as 11-18 cases per 100,000 people and 169 DALYs lost annually. Annual incidence in surrounding Districts was up to 85 per 100,000 persons. At our Moshi and Endulen sites the most commonly reactive serogroups were Australis and Djasiman. The systematic review found that serovars from the Australis serogroup have been isolated in Africa from field rats, multi-mammate rats, and cattle. Serovars of the Djasiman serogroup have not been isolated in Africa but have been isolated from dogs and small mammals in South America, Asia, and Europe. Using PCR, we identified L. borgpetersenii, L. interrogans, and L. kirschneri in the serum of patients with fever. Working in rice fields (odds ratio [OR] 14.6, 95% confidence intervals [CI] 2.9-59.5), cleaning cattle waste (OR 4.3, CI 1.2-12.9), feeding cattle (OR 3.9, CI 1.3-10.3) and being a farmer (OR 3.3, CI 1.3-8.2) were risk factors for acute leptospirosis. Increasing cumulative cattle urine exposure (OR 2.3, CI 1.1-4.7) and rodent urine exposure (OR 1.7, CI 1.1-2.8) were associated with leptospirosis on bivariable but not multivariable logistic regression. Working in rice fields (OR 3.6, 95% CI 1.5-9.0), slaughtering goats (OR 2.3, 95% CI 1.0-4.8), working as a farmer (OR 1.8, 95% CI 1.3-2.5), and frequently seeing rodents in the kitchen (OR 1.5, 95% CI 1.1-2.1) were risk factors for Leptospira seropositivity. All IgM point-of-care assays had low sensitivity compared with MAT. Leptospirosis causes substantial morbidity in northern Tanzania. Prevention of Leptospira infection in livestock is likely to reduce the burden of human leptospirosis. Clinicians should suspect leptospirosis in patients with fever who are rice workers or exposed to cattle urine, however IgM point-of-care tests are insufficiently accurate for clinical use

A preferred vision for administering secondary schools: A reflective essay

The purpose of this paper is to articulate the fundamental values and beliefs which will lend guidance as I prepare to enter the field of administration. It is important that I establish myself as a professional educator, whose primary allegiance is to properly educate students and develop their minds so they may reason and think abstractly. I have been often asked why would a young man like myself want to teach in the public school system, where so many children are disobedient? My only rationale is that I love children and what other way is there to touch so many lives in such a positive way. Upon completion of high school, I knew that I wanted to be an educator, but pressure from my parents to be an accountant superseded my decision. I chose and completed a major in business administration with a minor in economics and accounting, but I was not happy! I knew I wanted to be an educator and go on to be a principal. I returned to college and completed a post-baccalaureate certification program in education. Upon entering the masters program here at the University of Northern Iowa, I knew that the job of a principal was time consuming and demanding, but what I did not know was 2 that it is the most difficult job in education. I await the challenge of becoming a principal to continue the support of promoting education and advancing civilization through educating America\u27s youth

StreamIt: A Language and Compiler for Communication-Exposed Architectures

With the increasing miniaturization of transistors, wire delays are becoming a dominant factor in microprocessor performance. To address this issue, a number of emerging architectures contain replicated processing units with software-exposed communication between one unit and another (e.g., Raw, SmartMemories, TRIPS). However, for their use to be widespread, it will be necesary to develop a common machine language to allow programmers to express an algorithm in a way that can be efficiently mapped across these architectures. We propose a new common machine language for grid-based software-exposed architectures: StreamIt. StreamIt is a high-level programming language with explicit support for streaming computation. Unlike sequential programs with obscured dependence information and complex communication patterns, a stream program is naturally written as a set of concurrent filters with regular steady-state communication. The language imposes a hierarchical structure on the stream graph that enables novel representations and optimizations within the StreamIt compiler. We have implemented a fully functional compiler that parallelizes StreamIt applications for Raw, including several load-balancing transformations. Though StreamIt exposes the parallelism and communication patterns of stream programs, analysis is needed to adapt a stream program to a software-exposed processor. We describe a partitioning algorithm that employs fission and fusion transformations to adjust the granularity of a stream graph, a layout algorithm that maps a stream graph to a given network topology, and a scheduling strategy that generates a fine-grained static communication pattern for each computational element. Using the cycle-accurate Raw simulator, we demonstrate that the StreamIt compiler can automatically map a high-level stream abstraction to Raw. We consider this work to be a first step towards a portable programming model for communication-exposed architectures.Singapore-MIT Alliance (SMA

Prevalence and risk factors for Q fever, spotted fever grouprickettsioses, and typhus group rickettsioses in a pastoralistcommunity of northern Tanzania, 2016–2017

A research article was published by Tropical Medicine & International Health, 2024Background: In northern Tanzania, Q fever, spotted fever group (SFG) rickettsioses, and typhus group (TG) rickettsioses are common causes of febrile illness. We sought to describe the prevalence and risk factors for these zoonoses in a pastoralist community. Methods: Febrile patients ≥2 years old presenting to Endulen Hospital in the Ngorongoro Conservation Area were enrolled from August 2016 through October 2017. Acute and convalescent blood samples were collected, and a questionnaire was administered. Sera were tested by immunofluorescent antibody (IFA) IgG assays using Coxiella burnetii (Phase II), Rickettsia africae, and Rickettsia typhi antigens. Serologic evidence of exposure was defined by an IFA titre ≥1:64; probable cases by an acute IFA titre ≥1:128; and confirmed cases by a ≥4-fold rise in titre between samples. Risk factors for exposure and acute case status were evaluated. Results: Of 228 participants, 99 (43.4%) were male and the median (interquartile range) age was 27 (16–41) years. Among these, 117 (51.3%) had C. burnetii exposure, 74 (32.5%) had probable Q fever, 176 (77.2%) had SFG Rickettsia exposure, 134 (58.8%) had probable SFG rickettsioses, 11 (4.8%) had TG Rickettsia exposure, and 4 (1.8%) had probable TG rickettsioses. Of 146 participants with paired sera, 1 (0.5%) had confirmed Q fever, 8 (5.5%) had confirmed SFG rickettsioses, and none had confirmed TG rickettsioses. Livestock slaughter was associated with acute Q fever (adjusted odds ratio [OR] 2.54, 95% confidence interval [CI] 1.38–4.76) and sheep slaughter with SFG rickettsioses case (OR 4.63, 95% CI 1.08–23.50). Discussion: Acute Q fever and SFG rickettsioses were detected in participants with febrile illness. Exposures to C. burnetii and to SFG Rickettsia were highly prevalent, and interactions with livestock were associated with increased odds of illness with both path- ogens. Further characterisation of the burden and risks for these diseases is warranted

Risk factors for human brucellosis in northern Tanzania

Little is known about the epidemiology of human brucellosis in sub-Saharan Africa. This hampers prevention and control efforts at the individual and population levels. To evaluate risk factors for brucellosis in northern Tanzania, we conducted a study of patients presenting with fever to two hospitals in Moshi, Tanzania. Serum taken at enrollment and at 4–6 week follow-up was tested by Brucella microagglutination test. Among participants with a clinically compatible illness, confirmed brucellosis cases were defined as having a ≥ 4-fold rise in agglutination titer between paired sera or a blood culture positive for Brucella spp., and probable brucellosis cases were defined as having a single reciprocal titer ≥ 160. Controls had reciprocal titers < 20 in paired sera. We collected demographic and clinical information and administered a risk factor questionnaire. Of 562 participants in the analysis, 50 (8.9%) had confirmed or probable brucellosis. Multivariable analysis showed that risk factors for brucellosis included assisting goat or sheep births (Odds ratio [OR] 5.9, 95% confidence interval [CI] 1.4, 24.6) and having contact with cattle (OR 1.2, 95% CI 1.0, 1.4). Consuming boiled or pasteurized dairy products was protective against brucellosis (OR 0.12, 95% CI 0.02, 0.93). No participants received a clinical diagnosis of brucellosis from their healthcare providers. The under-recognition of brucellosis by healthcare workers could be addressed with clinician education and better access to brucellosis diagnostic tests. Interventions focused on protecting livestock keepers, especially those who assist goat or sheep births, are needed

Risk factors for human acute leptospirosis in northern Tanzania

Introduction: Leptospirosis is a major cause of febrile illness in Africa but little is known about risk factors for human infection. We conducted a cross-sectional study to investigate risk factors for acute leptospirosis and Leptospira seropositivity among patients with fever attending referral hospitals in northern Tanzania. Methods: We enrolled patients with fever from two referral hospitals in Moshi, Tanzania, 2012–2014, and performed Leptospira microscopic agglutination testing on acute and convalescent serum. Cases of acute leptospirosis were participants with a four-fold rise in antibody titers, or a single reciprocal titer ≥800. Seropositive participants required a single titer ≥100, and controls had titers <100 in both acute and convalescent samples. We administered a questionnaire to assess risk behaviors over the preceding 30 days. We created cumulative scales of exposure to livestock urine, rodents, and surface water, and calculated odds ratios (OR) for individual behaviors and for cumulative exposure variables. Results: We identified 24 acute cases, 252 seropositive participants, and 592 controls. Rice farming (OR 14.6), cleaning cattle waste (OR 4.3), feeding cattle (OR 3.9), farm work (OR 3.3), and an increasing cattle urine exposure score (OR 1.2 per point) were associated with acute leptospirosis. Conclusions: In our population, exposure to cattle and rice farming were risk factors for acute leptospirosis. Although further data is needed, these results suggest that cattle may be an important source of human leptospirosis. Further investigation is needed to explore the potential for control of livestock Leptospira infection to reduce human disease

Incidence of human brucellosis in the Kilimanjaro Region of Tanzania in the periods 2007-2008 and 2012-2014

Background: Brucellosis causes substantial morbidity among humans and their livestock. There are few robust estimates of the incidence of brucellosis in sub-Saharan Africa. Using cases identified through sentinel hospital surveillance and health care utilization data, we estimated the incidence of brucellosis in Moshi Urban and Moshi Rural Districts, Kilimanjaro Region, Tanzania, for the periods 2007–2008 and 2012–2014. Methods: Cases were identified among febrile patients at two sentinel hospitals and were defined as having either a 4-fold increase in Brucella microscopic agglutination test titres between acute and convalescent serum or a blood culture positive for Brucella spp. Findings from a health care utilization survey were used to estimate multipliers to account for cases not seen at sentinel hospitals. Results: Of 585 patients enrolled in the period 2007–2008, 13 (2.2%) had brucellosis. Among 1095 patients enrolled in the period 2012–2014, 32 (2.9%) had brucellosis. We estimated an incidence (range based on sensitivity analysis) of brucellosis of 35 (range 32–93) cases per 100 000 persons annually in the period 2007–2008 and 33 (range 30–89) cases per 100 000 persons annually in the period 2012–2014. Conclusions: We found a moderate incidence of brucellosis in northern Tanzania, suggesting that the disease is endemic and an important human health problem in this area

Comparison of the estimated incidence of acute leptospirosis in the Kilimanjaro Region of Tanzania between 2007-08 and 2012-14

Background: The sole report of annual leptospirosis incidence in continental Africa of 75–102 cases per 100,000 population is from a study performed in August 2007 through September 2008 in the Kilimanjaro Region of Tanzania. To evaluate the stability of this estimate over time, we estimated the incidence of acute leptospirosis in Kilimanjaro Region, northern Tanzania for the time period 2012–2014. Methodology and Principal Findings: Leptospirosis cases were identified among febrile patients at two sentinel hospitals in the Kilimanjaro Region. Leptospirosis was diagnosed by serum microscopic agglutination testing using a panel of 20 Leptospira serovars belonging to 17 separate serogroups. Serum was taken at enrolment and patients were asked to return 4–6 weeks later to provide convalescent serum. Confirmed cases required a 4-fold rise in titre and probable cases required a single titre of ≥800. Findings from a healthcare utilisation survey were used to estimate multipliers to adjust for cases not seen at sentinel hospitals. We identified 19 (1.7%) confirmed or probable cases among 1,115 patients who presented with a febrile illness. Of cases, the predominant reactive serogroups were Australis 8 (42.1%), Sejroe 3 (15.8%), Grippotyphosa 2 (10.5%), Icterohaemorrhagiae 2 (10.5%), Pyrogenes 2 (10.5%), Djasiman 1 (5.3%), Tarassovi 1 (5.3%). We estimated that the annual incidence of leptospirosis was 11–18 cases per 100,000 population. This was a significantly lower incidence than 2007–08 (p<0.001). Conclusions: We estimated a much lower incidence of acute leptospirosis than previously, with a notable absence of cases due to the previously predominant serogroup Mini. Our findings indicate a dynamic epidemiology of leptospirosis in this area and highlight the value of multi-year surveillance to understand leptospirosis epidemiology

Sensing remote nuclear spins

Sensing single nuclear spins is a central challenge in magnetic resonance based imaging techniques. Although different methods and especially diamond defect based sensing and imaging techniques in principle have shown sufficient sensitivity, signals from single nuclear spins are usually too weak to be distinguished from background noise. Here, we present the detection and identification of remote single C-13 nuclear spins embedded in nuclear spin baths surrounding a single electron spins of a nitrogen-vacancy centre in diamond. With dynamical decoupling control of the centre electron spin, the weak magnetic field ~10 nT from a single nuclear spin located ~3 nm from the centre with hyperfine coupling as weak as ~500 Hz is amplified and detected. The quantum nature of the coupling is confirmed and precise position and the vector components of the nuclear field are determined. Given the distance over which nuclear magnetic fields can be detected the technique marks a firm step towards imaging, detecting and controlling nuclear spin species external to the diamond sensor