Prevalence and intensity of soil-transmitted helminth infections of children in sub-Saharan Africa, 2000-18: a geospatial analysis

Background

Driven by global targets to eliminate soil-transmitted helminths as a public health problem, governments have rapidly rolled out control programmes using school and community-based platforms. To justify and target ongoing investment, quantification of impact and identification of remaining high-risk areas are needed. We aimed to assess regional progress towards these targets.

Methods

We did a continental-scale ecological analysis using a Bayesian space–time hierarchical model to estimate the effects of known environmental, socioeconomic, and control-related factors on the prevalence of soil-transmitted helminths, and we mapped the probability that implementation units had achieved moderate-to-heavy intensity infection prevalence of less than 2% among children aged 5–14 years between Jan 1, 2000, and Dec 31, 2018.

Findings

We incorporated data from 26 304 georeferenced surveys, spanning 3096 (60%) of the 5183 programmatic implementation units. Our findings suggest a reduction in the prevalence of soil-transmitted helminths in children aged 5–14 years in sub-Saharan Africa, from 44% in 2000 to 13% in 2018, driven by sustained delivery of preventive chemotherapy, improved sanitation, and economic development. Nevertheless, 1301 (25%) of 5183 implementation units still had an estimated prevalence of moderate-to-heavy intensity infection exceeding the 2% target threshold in 2018, largely concentrated in nine countries (in 1026 [79%] of 1301 implementation units): Nigeria, Democratic Republic of the Congo, Ethiopia, Cameroon, Angola, Mozambique, Madagascar, Equatorial Guinea, and Gabon.

Interpretation

Our estimates highlight the areas to target and strengthen interventions, and the areas where data gaps remain. If elimination of soil-transmitted helminths as a public health problem is to be achieved in sub-Saharan Africa by 2030, continued investment in treatment and prevention activities are essential to ensure that no areas are left behind.

Funding

Bill & Melinda Gates Foundation.

Supportive consensus

The paper is concerned with the consensus problem in a multi-agent system such that each agent has boundary constraints. Classical Olfati-Saber’s consensus algorithm converges to the same value of the consensus variable, and all the agents reach the same value. These algorithms find an equality solution. However, what happens when this equality solution is out of the range of some of the agents? In this case, this solution is not adequate for the proposed problem. In this paper, we propose a new kind of algorithms called supportive consensus where some agents of the network can compensate for the lack of capacity of other agents to reach the average value, and so obtain an acceptable solution for the proposed problem. Supportive consensus finds an equity solution. In the rest of the paper, we define the supportive consensus, analyze and demonstrate the network’s capacity to compensate out of boundaries agents, propose different supportive consensus algorithms, and finally, provide some simulations to show the performance of the proposed algorithms.

Evaluating survey designs for targeting preventive chemotherapy against Schistosoma haematobium and Schistosoma mansoni across sub-Saharan Africa: a geostatistical analysis and modelling study

BACKGROUND

Schistosomiasis control programmes primarily use school-based surveys to identify areas for mass drug administration of preventive chemotherapy. However, as the spatial distribution of schistosomiasis can be highly focal, transmission may not be detected by surveys implemented at districts or larger spatial units. Improved mapping strategies are required to accurately and cost-effectively target preventive chemotherapy to remaining foci across all possible spatial distributions of schistosomiasis.

METHODS

Here, we use geostatistical models to quantify the spatial heterogeneity of Schistosoma haematobium and S. mansoni across sub-Saharan Africa using the most comprehensive dataset available on school-based surveys. Applying this information to parameterise simulations, we assess the accuracy and cost of targeting alternative implementation unit sizes across the range of plausible schistosomiasis distributions. We evaluate the consequences of decisions based on survey designs implemented at district and subdistrict levels sampling different numbers of schools. Cost data were obtained from field surveys conducted across multiple countries and years, with cost effectiveness evaluated as the cost per correctly identified school.

RESULTS

Models identified marked differences in prevalence and spatial distributions between countries and species; however, results suggest implementing surveys at subdistrict level increase the accuracy of treatment classifications across most scenarios. While sampling intensively at the subdistrict level resulted in the highest classification accuracy, this sampling strategy resulted in the highest costs. Alternatively, sampling the same numbers of schools currently recommended at the district level but stratifying by subdistrict increased cost effectiveness.

CONCLUSIONS

This study provides a new tool to evaluate schistosomiasis survey designs across a range of transmission settings. Results highlight the importance of considering spatial structure when designing sampling strategies, illustrating that a substantial proportion of children may be undertreated even when an implementation unit is correctly classified. Control programmes need to weigh the increased accuracy of more detailed mapping strategies against the survey costs and treatment priorities.

Refocusing vector assessment towards the elimination of onchocerciasis from Africa: a review of the current status in selected countries

Measures to control onchocerciasis have been in place for well over 30 years. Recently, programs have turned from disease control towards transmission elimination. The absence of infective larvae in the black fly Simulium sp. vector is central to defining elimination, and assessments of infectivity by O150 polymerase chain reaction in the vector not only provide valuable information to programs, but are also required for verification of elimination. The status of transmission in black flies was assessed in five countries in the African region during 2014 and 2015. Several of these countries were evaluated because of promising results from epidemiological studies in humans. No infective flies were found in two countries. Infective flies were found in the other three, despite the absence of infection in humans (as evaluated by skin-snip microscopy). Ongoing transmission as demonstrated in the black flies could be due to a variety of factors, including lack of treatment of hypo-endemic areas and cross-border issues. Challenges identified during the course of the entomological work suggest that there is a need for improved selection of vector collection sites and vector collection periods in order to improve fly catches. Two important challenges to achieving elimination identified were definition of the hypo-endemic zones and establishing the existence of areas of cross-border transmission occurring between countries.

Use of Antibody Tools to Provide Serologic Evidence of Elimination of Lymphatic Filariasis in The Gambia

A current need in the global effort to eliminate lymphatic filariasis (LF) is the availability of reliable diagnostic tools that can be used to guide programmatic decisions, especially decisions made in the final stages of the program. This study conducted in The Gambia aimed to assess antifilarial antibody levels among populations living in historically highly LF-endemic areas and to evaluate the use of serologic tools to confirm the interruption of LF transmission. A total of 2,612 dried blood spots (DBSs) collected from individuals aged 1 year and above from 15 villages were tested for antibodies to Wb123 by enzyme-linked immunosorbent assay (ELISA). A subset of DBS (N = 599) was also tested for antibodies to Bm14 by ELISA. Overall, the prevalence of Wb123 was low (1.5%, 95% confidence interval [CI] 1.1-2.1%). In 7 of 15 villages (46.7%), there were no Wb123-positive individuals identified. Individuals with positive responses to Wb123 ranged in age from 3 to 100 years. Overall, Bm14 prevalence was also low (1.5%, 95% CI 0.7-2.8%). Bm14 positivity was significantly associated with older age (P < 0.001). The low levels of antibody responses to Wb123 observed in our study strongly suggest that sustainable LF transmission has likely ceased in The Gambia. In addition, our results support the conclusion that serologic tools can have a role in guiding programmatic decision making and supporting surveillance.

Preventive chemotherapy as a strategy for elimination of neglected tropical parasitic diseases: endgame challenges

Global efforts to address neglected tropical diseases (NTDs) were stimulated in January 2012 by the London declaration at which 22 partners, including the Bill & Melinda Gates Foundation, World Bank, World Health Organization (WHO) and major pharmaceutical companies committed to sustaining and expanding NTD programmes to eliminate or eradicate 11 NTDs by 2020 to achieve the goals outlined in the recently published WHO road map. Here, we present the current context of preventive chemotherapy for some NTDs, and discuss the problems faced by programmes as they consider the 'endgame', such as difficulties of access to populations in post-conflict settings, limited human and financial resources, and the need to expand access to clean water and improved sanitation for schistosomiasis and soil-transmitted helminthiasis. In the case of onchocerciasis and lymphatic filariasis, ivermectin treatment carries a significant risk owing to serious adverse effects in some patients co-infected with the tropical eye worm Loa loa filariasis. We discuss the challenges of managing complex partnerships, and maintain advocacy messages for the continued support for elimination of these preventable diseases.

Contribution of 18F-sodium fluoride PET/CT to the study of the carotid atheroma calcification

AIM

To assess the calcification process of the carotid plaque by (18)F-sodium fluoride PET/CT imaging.

MATERIAL AND METHODS

A prospectively designed study including 15 patients in whom an atheroma plaque was detected by contrast enhanced CT scan during a neurological work-up was performed. A total of 29 plaques, 19 asymptomatic and 10 symptomatic, were studied. An (18)F-sodium fluoride PET/CT scan was acquired 180min after the i.v. injection of 370 MBq of (18)F-sodium fluoride in all the patients. The images obtained were analyzed visually according to the intensity of the uptake.

RESULTS

All the plaques showed (18)F-sodium fluoride uptake, regardless of the intensity. However, the plaques of the symptomatic group showed a level of 2 or greater intensity while the intensity in 6 of the 19 in the asymptomatic group was lower than 2.

CONCLUSIONS

Although the study is limited by the small number of cases, the results show the feasibility of the technique to study the calcification of the atheroma using (18)F-sodium fluoride and suggest an association between symptomatology and higher uptake of (18)F-sodium fluoride. Thus, these results encourage us to continue this study, with the inclusion of a larger number of patients.

[Plan for stroke healthcare delivery]

INTRODUCTION

All stroke patients should receive the same degree of specialized healthcare attention according to the stage of their disease, independently of where they live, their age, gender or ethnicity.

OBJECTIVE

To create an organized healthcare system able to offer the needed care for each patient, optimizing the use of the existing resource.

METHODS

A committee of 14 neurologists specialized in neurovascular diseases representing different regions of Spain evaluated the available scientific evidence according to the published literature.

RESULTS

During the acute phase, all stroke patients must be evaluated in hospitals that offer access to specialized physicians (neurologists) and the indicated diagnostic and therapeutic procedures. Hospitals that deliver care to acute stroke patients must be prepared to attend these patients and need to arrange a predefined transferring circuit coordinated with the extrahospitalary emergency service. Since resources are limited, they should be structured into different care levels according to the target population. Thus, three types of hospitals will be defined for stroke care: reference stroke hospital, hospital with stroke unit, hospital with stroke team.

Characterisation of fluoroquinolone-resistant clinical isolates of Streptococcus pyogenes in Barcelona, Spain

Resistance mechanisms and clonal relationships were determined for six Streptococcus pyogenes isolates with low- or high-level ciprofloxacin resistance. Four isolates displayed reduced susceptibility to ciprofloxacin and levofloxacin and had alterations in ParC: Ser80-->Pro (isolate emm3.1); Ser79-->Ala (two isolates emm6.0); and a double substitution Ser79-->Phe and Ala121-->Val (isolate emm12.27). Two isolates (emm12.26) displayed high-level resistance to ciprofloxacin and levofloxacin, as well as to other quinolones. These isolates had the same double substitution in ParC as isolate emm12.27, and an additional substitution (Ser81-->Tyr) in GyrA. Resistance patterns, emm typing and sequencing of the quinolone resistance-determining regions defined two clusters containing three and two isolates, respectively.

Splenic abscesses caused by Actinomyces meyeri in a patient with autoimmune hepatitis

We report a case of actinomycosis with uncommon localizations that was due to Actinomyces meyeri. Although penicillin is the standard treatment for this condition, our patient was treated successfully with imipenem. Actinomyces organisms are important constituents of the normal flora of mucous membranes and are considered opportunistic pathogens; these organisms may produce infection after local trauma, surgery, or aspiration. The mains forms of actinomycosis are cervicofacial, thoracic, and abdominal; most cases are due to Actinomyces israelii, whereas other Actinomyces species are occasionally implicated. Actinomycosis usually occurs in immunocompetent persons, but may occur in persons with diminished host defenses.

[Osterosclerotic myeloma and polyneuropathy]

INTRODUCTION

The peripheral neuropathy is a common complication in patients with osteosclerotic myeloma. The association with hepatosplenomegaly, lymphadenopathy and variable endocrine disturbances and skin changes constitute the POEMS syndrome. The pathogenesis of this syndrome is unclear, but the presence of M protein and elevated levels of interleukin-6 in the serum of patients, suggests an immunologic mechanism.

CASE

A 68 year old woman presented with a 2 year history of progressive weakness and paresthesias in both legs. Neurological examination revealed a sensorimotor polyneuropathy, involving predominantly the lower extremities. In addition to neurological findings, the patient had lymphadenopathy and skin hyperpigmentation. Serum protein immunoelectrophoresis revealed a peak of monoclonal IgA lambda paraprotein. Radiographic examination disclosed multiple osteosclerotic lesions. Electrophysiological evaluation showed a severe axonal and demyelinating sensorimotor polyneuropathy. Biopsy of sural nerve revealed demyelination and axonal degeneration. Axillary lymph node biopsy were consistent with giant lymph node hyperplasia. Interleukin-6 serum levels were normal.

CONCLUSIONS

The POEMS syndrome or Crow-Fusake syndrome is a rare multisystem disorder often associated with osteosclerotic myeloma. A severe demyelinating sensorimotor polyneuropathy frequently constitutes the chief complaint. These patients have a polyneu-ropathy which resembles idiopathic chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and the electrophysi-ological studies are essential in the diagnosis. The pathogenesis has not been explained. Presumably, the plasma cells secrete an immunoglobulin or another substance that is toxic to peripheral nerves. Interleukin-6 is implicated in the pathogenesis of this disease.

Intramedullary tuberculoma of the spinal cord with syringomyelia

We describe a patient with a presumed intramedullary tuberculoma treated only with antituberculous therapy. MRI showed a ring-enhancing annular lesion in the thoracic spinal cord with a distant syringomyelic cavity, which improved after therapy. MRI in this case allowed us not only to achieve a presumptive diagnosis but also to assess the therapeutic response, making surgical exploration unnecessary.

Etiologic study of stroke in 95 young adults

The aim of this prospective study was to determine the etiologic factors leading to stroke in a group of young adults. We studied 95 patients aged 50 years or under who were admitted with the diagnosis of stroke over a 2-year period. These patients underwent complete clinical and laboratory assessment for stroke. The etiology was established in 73 (76.8%) out of 95 cases. Arterial hypertension, embolism and atherosclerosis were found to be the most frequent causes in patients with ischemic stroke, whereas hypertension and aneurysm rupture were the most prevailing etiologies in patients with hemorrhagic stroke. Miscellaneous causes represented one fourth of all cases of the series. Coagulation abnormalities occurred in some patients, but in these cases there were also other well established causes. Paradoxical embolism was not observed. This study corroborates the importance of thorough diagnostic evaluation to establish an accurate diagnosis.

[Distribution of headache by diagnosis as the reason for neurologic consultation]

BACKGROUND

The aim of this study was to analyze the diagnostic distribution of patients consulting because of headache in a neurology department.

METHODS

The clinical records of 3,498 patients who had consulted specifically due to headache between 1978 to 1993 were retrospectively studied. Diagnosis was reclassified according to the criteria of the new headache classification with data concerning the age of onset and sex distribution also being collected.

RESULTS

The most frequent diagnoses were migraine (1,802 patients; 52%) tension-type headache (113; 32%), followed in decreasing order by trigeminal neuralgia, post injury headache, cluster headache, subarachnoid hemorrhage, analgesic-ergotamine abuse headache, tumoral headache, cervical disease headache, benign exertional headache, due to paranasal sinusal disorders and benign intracranial hypertension. Female predominance was observed in the whole series (68%) as in the groups with migraine, tension-type headache, neuralgia headache by analgesic-ergotamine drugs and benign intracranial hypertension. Cluster, post injury, tumor and provoked headaches (cough, exertional and sexual) were found to be more frequent in men. The age of onset was very specific for each kind of headache. The percentage of symptomatic headaches increased in direct relation to age, being 10 fold higher in patients over the age of 65.

CONCLUSIONS

The diagnostic distribution of headache as a cause of medical consultation is very different to the prevalence of different headaches. This distribution by diagnosis largely depends on the age of the patient at the time of headaches onset [corrected].

Tegmental pontine hemorrhage with pure trigeminal motor impairment

We report a patient with a right dorsolateral pontine syndrome including right masticatory weakness without facial hypesthesia. Brain computed tomography showed a right dorsolateral pontine hemorrhage. Blink reflex study indicated preservation of spinal tracts and sensory nuclei of the trigeminal nerve. Right masseter electromyography revealed denervation. This patient provides a good correlation between clinical, radiological and electrophysiological findings and nuclear organisation of the trigeminal nerve.

[Possible use of serum calcitonin in septic patients at risk of acute respiratory distress syndrome]

The acute respiratory distress syndrome (ARDS) is a late complication in critically ill patients and its diagnosis is usually made when the syndrome is fully established. There is an increased interest in developing early markers that may help to identify ARDS in its initial stages. Calcitonin was recently reported as a useful serum marker to identify burned patients at risk for respiratory failure. We report a case with abdominal sepsis and ARDS, whose serum calcitonin level was 1000 pg/mL without other known clinical causes of hypercalcitoninemia and who died in multiorganic failure. The possible mechanisms of hypercalcitoninemia and its possible utility as marker of ARDS in critically ill patients is discussed.

Cerebral arterial occlusion and intracranial venous thrombosis in a woman taking oral contraceptives

Occlusion of the middle cerebral artery and thrombosis of the superior sagittal sinus are reported in a 30-year-old woman taking oral contraceptives (OC). The coexistence of arterial and venous cerebral pathology as a complication of OC use has only been previously reported in one case. The pathogenesis of this rare association is briefly discussed.

Livedo reticularis and cerebrovascular lesions (Sneddon's syndrome). Clinical, radiological and pathological features in eight cases

Eight patients with diffuse livedo reticularis and cerebrovascular lesions (Sneddon's syndrome) are reported. The disorder was inherited by autosomal dominant transmission in 3 cases. Multiple occlusions in medium-sized arteries were demonstrated by cerebral and hand arteriograms. Digital artery biopsies showed intimal hyperplasia in 7 cases and recanalized thrombosis in one case. Our findings are compared with an extensive review of the literature. Differential diagnosis with other vascular disorders, especially cerebral thromboangiitis obliterans and the corticomeningeal angiomatosis of Divry and Van Bogaert is considered. We conclude that Sneddon's syndrome is a new genetic and progressive arteriopathy, occlusive and noninflammatory, involving medium-sized vessels. The pathogenesis has yet to be elucidated.

Occipital dysplasia and Chiari type I deformity in a family. Clinical and radiological study of three generations

Three generations of a family affected by a craniocervical malformation (CCM) were subjected to clinical and radiological studies. Occipital dysplasia (OD) and Chiari type I deformity (CD.I) were the main features, inheritance being autosomal-dominant. The malformation was variably expressed; it ranged from OD with basilar impression (BI) to OD without BI and from CD.I with OD to CD.I without obvious osseous malformation. Its pathogenesis, and that of other related familial disorders (Klippel-Feil syndrome and syringomyelia), is discussed, the conclusion being drawn that all were elements of one genetic disorder which finds expression in a very variable sequence. The value of high-resolution CT in the detection of asymptomatic carriers is emphasized.

Giant aneurysm of the intracavernous carotid artery and bilateral carotid fibromuscular dysplasia

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Familial cerebellar ataxia and hypogonadotropic hypogonadism: evidence for hypothalamic LHRH deficiency

A family with familial cerebellar ataxia and hypogonadotropic hypogonadism is described. The condition was inherited as an autosomal recessive defect. CT scan in one case revealed cerebellar and brain stem atrophy. Endocrinological tests showed abnormalities only in two patients who were clinically affected. In both cases raised gonadotropic levels were found after repetitive stimulation with luteining hormone-releasing hormone which suggests that the hypogonadism was due to a primary hypothalamic disturbance.

Occipitoatlantal instability and vertebrobasilar ischemia: case report

A 37-year-old woman had occipitoatlantal instability due to hypoplasia of the occipital condyles. Neck pain and transient ischemic attacks in the vertebrobasilar territory occurred with extension of the neck, which also caused convergence spasm. Angiography demonstrated that these manifestations were due to compression of the vertebral arteries during neck extension. Immobilization of the neck in a Minerva cast resulted in complete relief of symptoms.

Thoracic spinal cord ependymoma presenting with ejaculatory failure. Case report

✓ A case of thoracic spinal cord ependymoma presenting with ejaculatory failure is described. This mode of onset has not previously been reported in patients with thoracic intraspinal tumors.

[Presence of resistance factors to antibiotics in multiresistant enterobacteria]

The present study was carried out with 111 multiresistant pathogenic strains of enterobacterias isolated from different sources with increased resistance to three or more antibiotics. Among the identified species are included E. coli, Shigella sp., Salmonella oranienburg, Klebsiella pneumoniae and Citrobacter freundii. In general, the minimal inhibitory concentration of antibiotics was above 100 microgram/ml and in some cases it was superior to 1000 microgram/ml. Resistance transfer factors were detected in 72% of the strains; 33% movilized the complete pattern of resistance and 67% did it partially because some of the determinants were not transfered. The Citrobacter strains show a high frequency of transference (10(-1)), while for the others species it was in the order of 10(-2)--10(-3). The use of a multi-inoculator allows to perform in a simple way the preliminar evaluation about the presence or absence of R transfer factors in multiresistant strains. This technique has shown good correlation with the data obtained by the usual dilution and plating method.