Time Series Analysis of Onchocerciasis Data from Mexico: A Trend towards Elimination

Lara-Ramírez, Edgar E.; Rodríguez‐Pérez, Mario A.; Pérez-Rodríguez, Miguel Ángel; Adeleke, M. A.; Orozco-Algarra, María E.; Arrendondo-Jiménez, Juan I.; Guo, Xianwu

doi:10.1371/journal.pntd.0002033

Cited by 10 publications

(6 citation statements)

References 29 publications

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“…However, more accurate estimation of the composite functions will be important for describing and analyzing the behaviour of the model. Thus the model will be combined with time series data in the future [80]. …”

Section: Discussionmentioning

confidence: 99%

Field transmission intensity of Schistosoma japonicum measured by basic reproduction ratio from modified Barbour’s model

Gao

Liu

et al. 2013

Parasites Vectors

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BackgroundSchistosomiasis japonica, caused by infection with Schistosoma japonicum, is still recognized as a major public health problem in the Peoples’ Republic of China. Mathematical modelling of schistosomiasis transmission has been undertaken in order to assess and project the effects of various control strategies for elimination of the disease. Seasonal fluctuations in transmission may have the potential to impact on the population dynamics of schistosomiasis, yet no model of S. japonicum has considered such effects. In this paper, we characterize the transmission dynamics of S. japonicum using a modified version of Barbour’s model to account for seasonal variation (SV), and investigate the effectiveness of the control strategy adopted in Liaonan village of Xingzi county, Jiangxi Province.MethodsWe use mathematical tools for stability analysis of periodic systems and derive expressions for the basic reproduction ratio of S. japonicum in humans; we parameterise such expressions with surveillance data to investigate the conditions for persistence or elimination of the disease in the study village. We perform numerical simulations and parametric sensitivity analysis to understand local transmission conditions and compare values of the basic reproductive ratio with and without seasonal fluctuations.ResultsThe explicit formula of the basic reproduction ratio for the SV-modified Barbour’s model is derived. Results show that the value of the basic reproduction ratio, R0, of Liaonan village, Xingzi county is located between 1.064 and 1.066 (very close to 1), for schistosomiasis transmission during 2006 to 2010, after intensification of control efforts.ConclusionsOur modified version of the Barbour model to account for seasonal fluctuations in transmission has the potential to provide better estimations of infection risk than previous models. Ignoring seasonality tends to underestimate R0 values albeit only marginally. In the absence of simultaneous R0 estimations for villages not under control interventions (such villages do not currently exist in China), it is difficult to assess whether control strategies have had a substantial impact on levels of transmission, as the parasite population would still be able to maintain itself at an endemic level, highlighting the difficulties faced by elimination efforts.

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Section: Discussionmentioning

confidence: 99%

Field transmission intensity of Schistosoma japonicum measured by basic reproduction ratio from modified Barbour’s model

Gao

Liu

et al. 2013

Parasites Vectors

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“…There are thus good prospects that elimination of onchocerciasis is well underway in the Americas [ 9 ] and may also have begun at different foci on the African continent [ 6 , 10 , 11 ]. However, currently there is a paucity of information on the actual situation in Central and Southern Africa, in particular with respect to vector transmission, albeit a significant proportion of these regions have been hyperendemic.…”

Section: Introductionmentioning

confidence: 99%

Ongoing Transmission of Onchocerca volvulus after 25 Years of Annual Ivermectin Mass Treatments in the Vina du Nord River Valley, in North Cameroon

Eisenbarth¹,

Achukwi²,

Renz³

2016

PLoS Negl Trop Dis

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BackgroundRecent reports of transmission interruption of Onchocerca volvulus, the causing agent of river blindness, in former endemic foci in the Americas, and more recently in West and East Africa, raise the question whether elimination of this debilitating disease is underway after long-term treatment of the population at risk with ivermectin. The situation in Central Africa has not yet been clearly assessed.Methods and findingsEntomologic data from two former endemic river basins in North Cameroon were generated over a period of 43 and 48 months to follow-up transmission levels in areas under prolonged ivermectin control. Moreover, epidemiologic parameters of animal-borne Onchocerca spp. transmitted by the same local black fly vectors of the Simulium damnosum complex were recorded and their impact on O. volvulus transmission success evaluated. With mitochondrial DNA markers we unambiguously confirmed the presence of infective O. volvulus larvae in vectors from the Sudan savannah region (mean Annual Transmission Potential 2009–2012: 98, range 47–221), but not from the Adamawa highland region. Transmission rates of O. ochengi, a parasite of Zebu cattle, were high in both foci.Conclusions/significanceThe high cattle livestock density in conjunction with the high transmission rates of the bovine filaria O. ochengi prevents the transmission of O. volvulus on the Adamawa plateau, whereas transmission in a former hyperendemic focus was markedly reduced, but not completely interrupted after 25 years of ivermectin control. This study may be helpful to gauge the impact of the presence of animal-filariae for O. volvulus transmission in terms of the growing human and livestock populations in sub-Saharan countries.

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“…We evaluated the four methods: SARIMA [15], simple LSTM, Seq2Seq, and Seq2Seq with attention models. The evaluation metrics considered here were the Pearson correlation coefficient and RMSE.…”

Section: Resultsmentioning

confidence: 99%

Sequence to Sequence with Attention for Influenza Prevalence Prediction using Google Trends

Kondo

Ishikawa

Kimura

2019

Proceedings of the 2019 3rd International Conference on Computational Biology and Bioinformatics

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Early prediction of the prevalence of influenza reduces its impact. Various studies have been conducted to predict the number of influenza-infected people. However, these studies are not highly accurate especially in the distant future such as over one month. To deal with this problem, we investigate the sequence to sequence (Seq2Seq) with attention model using Google Trends data to assess and predict the number of influenza-infected people over the course of multiple weeks. Google Trends data help to compensate the dark figures including the statistics and improve the prediction accuracy. We demonstrate that the attention mechanism is highly effective to improve prediction accuracy and achieves state-of-the art results, with a Pearson correlation and root-mean-square error of 0.996 and 0.67, respectively. However, the prediction accuracy of the peak of influenza epidemic is not sufficient, and further investigation is needed to overcome this problem.

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Time Series Analysis of Onchocerciasis Data from Mexico: A Trend towards Elimination

Cited by 10 publications

References 29 publications

Field transmission intensity of Schistosoma japonicum measured by basic reproduction ratio from modified Barbour’s model

Field transmission intensity of Schistosoma japonicum measured by basic reproduction ratio from modified Barbour’s model

Ongoing Transmission of Onchocerca volvulus after 25 Years of Annual Ivermectin Mass Treatments in the Vina du Nord River Valley, in North Cameroon

Sequence to Sequence with Attention for Influenza Prevalence Prediction using Google Trends

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