El Niño-southern oscillations and lathyrism epidemics

Abstract

Epidemics of lathyrism, a neurological syndrome of spastic paraparesis, have occurred during severe droughts in Europe, Asia, and Africa for millenia. Causation is linked to exposure to β-N-oxalyl-L-α,β-diaminopropionic acid (β-L-ODAP), a neurotoxin in Lathyrus sativus. Lathyrism shares neurological features with konzo, a syndrome of predominantly spastic paraparesis which occurs during droughts in East and Central Africa and is linked to El Niño activity. This study was done to determine the relationship of lathyrism epidemics to phases of El Niño-southern oscillation (ENSO) and Pacific decadal oscillation (PDO), and to propose a model to explain why the geospatial distributions of lathyrism and konzo are non-overlapping. Contingency table of phases of ENSO and occurrence of lathyrism epidemics in Central Provinces, India from 1833-1902 was created and odds ratio was calculated. Wavelet spectra of time series of annual occurrence of lathyrism in Rewah district, India, and its coherence with ENSO and PDO from 1894 to 1920 were performed. Lathyrism epidemic was associated with El Niño phase of ENSO, odds ratio 378 (95% 32-4475). Global spectra showed peaks at periodicities of 2.5 and 4.6 years for lathyrism; 2.7 and 5.0 years for PDO; and 2.5, 4.6, 7.0 years for ENSO. Spectrograms showed time-varying periodicities of 2.5-3.5 and 4.5-5.5 years for lathyrism; 2.0-3.0 and 6.5-9.0 years for ENSO; and 3.5 and 5.0 years for PDO, p < 0.0001. Spectral coherence were at 2.0-3.5 and 4.5-5.0 years for ENSO and lathyrism p < 0.0001, and 5.0 years for PDO and lathyrism p < 0.05. The droughts of El Niños initiate dependence on Lathyrus sativus, which exposes the population to neurotoxic β-L-ODAP. Public health control of lathyrism epidemics should include development of models to forecast El Niños and initiate food programmes in susceptible areas.

Socioeconomic determinants of farm household land allocation for grass pea production in North Wollo Zone of Amhara region, Ethiopia

“…Wealth of household was not a significant factor to affect the intensity of land use for grass pea. Hillocks and Maruthi (2012) and Oluwole (2015) indicated that poor households opted grass pea production. However, our results revealed that household wealth was positively associated with decision of growing grass crop.…”

“…At a global scale, land put under grass pea production is estimated at about 1.5 million ha annually that produce about 1.2 million tons of the pulse, indicating the importance of the crop (Yang and Zhang, 2005;Siddique et al, 2006;Kumar et al, 2011). Thus, despite its severe consequences on human health, grass pea remains an important crop for some segments of people of many countries (Siddique et al, 1996;Siddique et al, 2006;Kumar et al, 2011;Singh et al, 2013;Oluwole, 2015) including in Ethiopia (Getahun et al, 1999;Tekle-Haimanot et al, 2005;Urga et al, 2005;Fikre et al, 2010;Damene, 2014). Lathyrism is a health problem in Ethiopian highlands with very high prevalence rates in the Amhara region (where grass pea is largely produced) (Getahun et al, 1999;Fikre et al, 2010;Woldeamanuel et al, 2012).…”