scholarly journals Cutaneous leishmaniasis in northeastern Brazil: a critical appraisal of studies conducted in State of Pernambuco

2012 ◽  
Vol 45 (4) ◽  
pp. 425-429 ◽  
Author(s):  
Maria Edileuza Felinto de Brito ◽  
Maria Sandra Andrade ◽  
Filipe Dantas-Torres ◽  
Eduardo Henrique Gomes Rodrigues ◽  
Milena de Paiva Cavalcanti ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Complex Disease ◽  
Critical Appraisal ◽  
Control Strategies ◽  
Local Level ◽  
Leishmania Species ◽  
Current Control ◽  
Control Measures ◽  
Northeastern Brazil ◽  
Effective Control

American cutaneous leishmaniasis (ACL) is a complex disease with clinical and epidemiological features that may vary from region to region. In fact, at least seven different Leishmania species, including Leishmania (Viannia) braziliensis, Leishmania (Viannia) guyanensis, Leishmania (Viannia) lainsoni, Leishmania (Viannia) naiffi, Leishmania (Viannia) shawi, Leishmania (Viannia) lindenbergi, and Leishmania (Leishmania) amazonensis, have been implicated in the etiology of ACL in Brazil, and numerous phlebotomine sandfly species of the genus Lutzomyia have been regarded as putative or proven vectors. Because ACL is a focal disease, understanding the disease dynamics at the local level is essential for the implementation of more effective control measures. The present paper is a narrative review about the ACL epidemiology in Pernambuco, northeastern Brazil. Furthermore, the need for more effective diagnosis, treatment, control and prevention strategies for the affected populations is highlighted. This paper will provide researchers with a critical appraisal of ACL in Pernambuco. Hopefully, it will also be helpful for public health authorities to improve current control strategies against ACL at the state and country levels.

scholarly journals Phylogenetic Complexity of Morphologically Identified Anopheles squamosus in Southern Zambia

Insects ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 146
Author(s):  
Jordan Hoffman ◽  
Ilinca Ciubotariu ◽  
Limonty Simubali ◽  
Twig Mudenda ◽  
William Moss ◽  
...  
Keyword(s):  
Phylogenetic Relationships ◽  
Catchment Area ◽  
Control Strategies ◽  
Light Trap ◽  
Current Control ◽  
Control Measures ◽  
Morphological Identification ◽  
The Past ◽  
Blood Meal Source ◽  
Residual Malaria Transmission

Despite dramatic reductions in malaria cases in the catchment area of Macha Hospital, Choma District, Southern Province in Zambia, prevalence has remained near 1–2% by RDT for the past several years. To investigate residual malaria transmission in the area, this study focuses on the relative abundance, foraging behavior, and phylogenetic relationships of Anopheles squamosus specimens. In 2011, higher than expected rates of anthropophily were observed among “zoophilic” An. squamosus, a species that had sporadically been found to contain Plasmodium falciparum sporozoites. The importance of An. squamosus in the region was reaffirmed in 2016 when P. falciparum sporozoites were detected in numerous An. squamosus specimens. This study analyzed Centers for Disease Control (CDC) light trap collections of adult mosquitoes from two collection schemes: one performed as part of a reactive-test-and-treat program and the second performed along a geographical transect. Morphological identification, molecular verification of anopheline species, and blood meal source were determined on individual samples. Data from these collections supported earlier studies demonstrating An. squamosus to be primarily exophagic and zoophilic, allowing them to evade current control measures. The phylogenetic relationships generated from the specimens in this study illustrate the existence of well supported clade structure among An. squamosus specimens, which further emphasizes the importance of molecular identification of vectors. The primarily exophagic behavior of An. squamosus in these collections also highlights that indoor vector control strategies will not be sufficient for elimination of malaria in southern Zambia.

scholarly journals Timing and Route of Contamination of Patient Rooms With Healthcare-Associated Pathogens

2020 ◽  
Vol 41 (S1) ◽  
pp. s412-s412
Author(s):  
Sarah Redmond ◽  
Jennifer Cadnum ◽  
Basya Pearlmutter ◽  
Natalia Pinto Herrera ◽  
Curtis Donskey
Keyword(s):  
Acute Care Hospital ◽  
Current Control ◽  
Pathogen Transmission ◽  
Control Measures ◽  
Effective Control ◽  
Portable Devices ◽  
Care Hospital ◽  
Spa Typing ◽  
Persistent Problem ◽  
Healthcare Associated

Background: Transmission of healthcare-associated pathogens such as Clostridioides difficile and methicillin-resistant Staphylococcus aureus (MRSA) is a persistent problem in healthcare facilities despite current control measures. A better understanding of the routes of pathogen transmission is needed to develop effective control measures. Methods: We conducted an observational cohort study in an acute-care hospital to identify the timing and route of transfer of pathogens to rooms of newly admitted patients with negative MRSA nares results and no known carriage of other healthcare-associated pathogens. Rooms were thoroughly cleaned and disinfected prior to patient admission. Interactions of patients with personnel and portable equipment were observed, and serial cultures for pathogens were collected from the skin of patients and from surfaces, including those observed to come in contact with personnel and equipment. For MRSA, spa typing was used to determine relatedness of patient and environmental isolates. Results: For the 17 patients enrolled, 1 or more environmental cultures became positive for MRSA in rooms of 10 patients (59%), for C. difficile in rooms of 2 patients (12%) and for vancomycin-resistant enterococci (VRE) in rooms of 2 patients (12%). The patients interacted with an average of 2.4 personnel and 0.6 portable devices per hour of observation. As shown in Figure 1, MRSA contamination of the floor occurred rapidly as personnel entered the room. In a subset of patients, MRSA was subsequently recovered from patients’ socks and bedding and ultimately from the high-touch surfaces in the room (tray table, call button, bedrail). For several patients, MRSA isolates recovered from the floor had the same spa type as isolates subsequently recovered from other sites (eg, socks, bedding, and/or high touch surfaces). The direct transfer of healthcare-associated pathogens from personnel or equipment to high-touch surfaces was not detected. Conclusions: Healthcare-associated pathogens rapidly accumulate on the floor of patient rooms and can be transferred to the socks and bedding of patients and to high-touch surfaces. Healthcare facility floors may be an underappreciated source of pathogen dissemination not addressed by current infection control measures.Funding: NoneDisclosures: None

An experimental evaluation of conventional control measures against the sheep tick, Ixodes ricinus (L.) (Acari: Ixodidae). II. The dynamics of the tick-host interaction

1985 ◽  
Vol 75 (3) ◽  
pp. 501-518 ◽  
Author(s):  
Sarah E. Randolph ◽  
Gordon M. Steele
Keyword(s):  
Ixodes Ricinus ◽  
Control Method ◽  
Control Strategies ◽  
Stocking Density ◽  
Experimental Manipulation ◽  
Control Measures ◽  
Effective Control ◽  
Contact Rate ◽  
Host Interaction ◽  
Questing Ticks

AbstractThe experimental manipulation of separate, but originally identical, populations of Ixodes ricinus (L.) by applying three conventional tick control measures in different enclosures on naturally infested moorland in Wales allowed the elements of the tick-host interaction to be analysed quantitatively and the effectiveness of the control methods to be compared. From the relationship between the sheep stocking density and the numbers of questing ticks picked up by fortnightly blanket-dragging in each enclosure, the death rate of ticks during their activity season and the rate of contact between sheep and ticks were calculated. From this, it was possible to investigate the effect of different stocking densities on the feeding success of ticks. A major factor determining the much lower contact rate for larvae than for nymphs was the different spatial distribution of questing ticks, clumped for larvae and random for nymphs. The non-random use by sheep of the three different vegetation zones in the paddock resulted in the highest contact rate between sheep and ticks in the pasture area, but tick survival was apparently highest in the bog area. Combining these factors resulted in the prediction that the bracken area was the least favourable habitat for ticks. In the two enclosures where the sheep were not treated with acaricide the mean tick loads on the sheep were similar, but the lower overall use of the pasture by the sheep in the low stocking density enclosure (2/ha) resulted in slightly lower tick loads there compared with those in the high stocking density enclosure (4/ha). The numbers of ticks counted in the second year showed that pasture spelling was the most effective control method, acaricide treatment was less effective, and the benefits of halving the stocking density were marginal. The implications of these results for control strategies are discussed.

scholarly journals Comparison of small mammal prevalence of Leishmania (Leishmania) mexicana in five foci of cutaneous leishmaniasis in the State of Campeche, Mexico

2009 ◽  
Vol 51 (2) ◽  
pp. 87-94 ◽  
Author(s):  
N.R. Van Wynsberghe ◽  
S.B. Canto-Lara ◽  
E.I. Sosa-Bibiano ◽  
N.A. Rivero-Cárdenas ◽  
F.J. Andrade-Narváez
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Yucatan Peninsula ◽  
The State ◽  
Control Measures ◽  
Effective Control ◽  
Leishmania Mexicana ◽  
Wild Rodents ◽  
Terrestrial Mammals ◽  
Yucatán Peninsula ◽  
Reservoir Species

In the Yucatan Peninsula of Mexico, 95% of the human cases of Cutaneous Leishmaniasis are caused by Leishmania (Leishmania) mexicana with an incidence rate of 5.08 per 100,000 inhabitants. Transmission is limited to the winter months (November to March). One study on wild rodents has incriminated Ototylomys phyllotis and Peromyscus yucatanicus as primary reservoirs of L. (L.) mexicana in the focus of La Libertad, Campeche. In the present study, the prevalence of both infection and disease caused by L. (L.) mexicana in small terrestrial mammals were documented during five transmission seasons (1994-2004) in five foci of Leishmaniasis in the state of Campeche. Foci separated by only 100 km, with similar relative abundances of small mammals, were found to differ significantly in their prevalence of both symptoms and infection. Transmission rates and reservoir species seemed to change in space as well as in time which limited the implementation of effective control measures of the disease even in a small endemic area such as the south of the Yucatan Peninsula.

scholarly journals Control Strategies for the Third wave of COVID-19 infection in India: A Mathematical Model Incorporating Vaccine Effectiveness

2022 ◽  
Author(s):  
Ashutosh Mahajan ◽  
Namitha Sivadas ◽  
Pooja Panda
Keyword(s):  
Transmission Rate ◽  
Control Strategies ◽  
Control Measures ◽  
Disease Spread ◽  
Effective Control ◽  
Third Wave ◽  
Social Distancing ◽  
Vaccination Rates ◽  
New Variant ◽  
The Future

The waning effectiveness of the COVID-19 vaccines and the emergence of a new variant Omicron has given rise to the possibility of another outbreak of the infection in India. COVID-19 has caused more than 34 million reported cases and 475 thousand deaths in India so far, and it has affected the country at the root level, socially as well as economically. After going through different control measures, mass vaccination has been achieved to a large extent for the highly populous country, and currently under progress. India has already been hit by a massive second wave of infection in April-June, 2021 mainly due to the delta variant, and might see a third wave in the near future that needs to be controlled with effective control strategies. In this paper, we present a compartmental epidemiological model with vaccinations incorporating the dose-dependent effectiveness. We study a possible sudden outbreak of SARS-CoV2 variants in the future, and bring out the associated predictions for various vaccination rates and point out optimum control measures. Our results show that for transmission rate 30% higher than the current rate due to emergence of new variant or relaxation of social distancing conditions, daily new cases can peak to 250k in March 2022, taking the second dose effectiveness dropping to 50% in the future. A combination of vaccination and controlled lockdown or social distancing is the key to tackling the current situation and for the coming few months. Our simulation results show that social distancing measures show better control over the disease spread than the higher vaccination rates. <br>

scholarly journals Modeling the Effective Control Strategy for the Transmission Dynamics of Global Pandemic COVID-19

2020 ◽  
Author(s):  
M. H. A. Biswas ◽  
M. S. Khatun ◽  
A. K. Paul ◽  
M. R. Khatun ◽  
M. A. Islam ◽  
...  
Keyword(s):  
Maximum Principle ◽  
Control Strategies ◽  
Pontryagin’S Maximum Principle ◽  
Control Measures ◽  
Effective Control ◽  
Human Immune System ◽  
Pontryagin's Maximum Principle ◽  
Social Distancing ◽  
Novel Coronavirus ◽  
Major Factors

AbstractThe novel coronavirus disease (namely COVID-19) has taken attention because of its deadliness across the globe, causing a massive death as well as critical situation around the world. It is an infectious disease which is caused by newly discovered coronavirus. Our study demonstrates with a nonlinear model of this devastating COVID-19 which narrates transmission from human-to-human in the society. Pontryagin’s Maximum principle has also been applied in order to obtain optimal control strategies where the maintenance of social distancing is the major control. The target of this study is to find out the most fruitful control measures of averting coronavirus infection and eventually, curtailed of the COVID-19 transmission among people. The model is investigated analytically by using most familiar necessary conditions of Pontryagin’s maximum principle. Furthermore, numerical simulations have been performed to illustrate the analytical results. The analysis reveals that implementation of educational campaign, social distancing and developing human immune system are the major factors which can be able to plunge the scenario of becoming infected.

scholarly journals Critical Appraisal of Management Practices in Nepalese Guava Orchards

2005 ◽  
Vol 26 ◽  
pp. 127-133 ◽  
Author(s):  
AK Shrestha
Keyword(s):  
Management Practices ◽  
Critical Appraisal ◽  
Psidium Guajava ◽  
Control Measures ◽  
Effective Control ◽  
Peak Period ◽  
Rainfed Condition ◽  
Guava Fruit ◽  
Production Constraints ◽  
June July

A survey was conducted to appraise the guava farming in Nepal with respect to the orchard management practices, cultivar status and major production constraints during July- December 2001. Guava plantation was extensively distributed throughout terai, inner terai and mid hill districts ranging in altitude from 115 masl to 1600 masl. Indian varieties dominated the guava plantation in Nepal although mix population of both improved and local cultivars was reported in majority of orchards. Preponderance of seedling origin guava plantation was noticed. The management practices were poor. Over 80% of the orchards received neither FYM nor chemical fertilizer. Similarly, more than 90% of the orchards were under rainfed condition. The peak period of flowering was reported during April/May followed by Feb/March that may extend up to June/July. As a consequence, the fruit availability period is mainly restricted to four months, i.e. July/ August to Oct/Nov. Most of the growers pointed out guava wilt as the main biotic constraint in guava production. The outcomes indicted the urgent need to adopt the effective control measures against the guava wilt malady to flourish guava enterprise in Nepal. Furthermore, off-season production of guava fruit has the great potential in Nepalese market. Key words: cultivar, guava wilt, orchard, Psidium guajava J. Inst. Agric. Anim. Sci. 26:127-133 (2005)

WOMEN AND MALARIA—SPECIAL RISK AND APPROPRIATE CONTROL STRATEGY

PEDIATRICS ◽  
1995 ◽  
Vol 96 (1) ◽  
pp. 117-117
Author(s):  
R. Rueben
Keyword(s):  
Pregnant Women ◽  
Malaria Transmission ◽  
Falciparum Malaria ◽  
Malaria Control ◽  
Rural Areas ◽  
Control Strategies ◽  
Current Control ◽  
Control Measures ◽  
Control Programs ◽  
Utility Distribution

The factors that make pregnant women particularly vulnerable to morbidity and mortality with falciparum malaria and their relationship to current control strategies are reviewed. Pregnant women, particularly during their first pregnancy, are at greatest risk of severe falciparum malaria in areas of high and continuous malaria transmission and under conditions of unstable malaria in which they do not develop protective immunity. The author recommends chemoprophylaxis with chloroquine for pregnant women living in holoendemic and hyperendemic areas of Africa and Papua, New Guinea. Chloroquine is safe, but drug resistance has increasingly limited its utility, distribution is a formidable problem. In rural areas where poorly developed health care system are better developed and malaria transmission is less intense, the emphasis should be on early diagnosis and treatment. Women are potentially the key to the implementation of malaria control programs, yet recent studies indicate that underprivileged women frequently do not attend malaria clinics and are often missed in projects with passive surveillance. Additional research and community interventions are needed to enable women with malaria to obtain treatment and to involve them in malaria control measures at the village level.

scholarly journals A model for evaluating intervention strategies to control salmonella in the poultry meat production chain

2000 ◽  
Vol 124 (3) ◽  
pp. 365-373 ◽  
Author(s):  
M. J. NAUTA ◽  
A. W. VAN DE GIESSEN ◽  
A. M. HENKEN
Keyword(s):  
Control Strategies ◽  
Intervention Strategies ◽  
Control Measures ◽  
Poultry Meat ◽  
Effective Control ◽  
Meat Production ◽  
Policy Makers ◽  
Production Chain ◽  
Transmission Parameters ◽  
Salmonella Control

A model of the transmission of salmonella through the poultry meat production chain is developed, to predict the effects of intervention strategies for salmonella control. The model first describes the situation before intervention in terms of salmonella prevalences at flock level and some transmission parameters. After single control measures are translated into effects on these transmission parameters, the effects of sets of control measures (intervention strategies), can be calculated with the model. As research data are lacking, the model input parameters were derived from expert opinion. As an example, the effects of two intervention strategies proposed for the Dutch poultry industry are predicted. A sensitivity analysis is performed to indicate where the most effective control measures may be expected. Additionally, the reliability of the model predictions is studied by an uncertainty analysis. The use of the model as a tool for policy makers deciding about salmonella control strategies is discussed.

scholarly journals Schistosoma transmission in a dynamic seasonal environment and its impact on the effectiveness of disease control

2020 ◽  
Author(s):  
Qimin Huang ◽  
David Gurarie ◽  
Martial Ndeffo-Mbah ◽  
Emily Li ◽  
Charles H King
Keyword(s):  
Seasonal Variation ◽  
Intermediate Host ◽  
Control Strategies ◽  
Control Measures ◽  
Seasonal Effects ◽  
Effective Control ◽  
Optimal Timing ◽  
Snail Population ◽  
Dynamics And Control ◽  
The Impact

Abstract Background A seasonal transmission environment including seasonal variation of snail population density and human-snail contact patterns can affect the dynamics of Schistosoma infection and the success of control interventions. In projecting control outcomes, conventional modeling approaches have often ignored seasonality by using simplified intermediate-host modeling, or by restricting seasonal effects through use of yearly averaging. Methods We used mathematical analysis and numerical simulation to estimate the impact of seasonality on disease dynamics and control outcomes, and to evaluate whether seasonal averaging or intermediate-host reduction can provide reliable predictions of control outcomes. We also examined whether seasonality could be used as leverage in creation of effective control strategies. Results We found models that used seasonal averaging could grossly overestimate infection burden and underestimate control outcomes in highly seasonal environments. We showed that proper intra-seasonal timing of control measures could make marked improvement on the long-term burden reduction for Schistosoma transmission control, and we identified the optimal timing for each intervention. Seasonal snail control, implemented alone, was less effective than mass drug administration, but could provide additive impact in reaching control and elimination targets. Conclusion Seasonal variation makes Schistosoma transmission less sustainable and easier to control than predicted by earlier modeling studies.

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