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Background and Objective: Malaria is a disease affecting 300–500 million people in tropical and subtropical regions and causes approximately 2.7 million deaths annually. Currently, no vaccine protects against malaria and resistance to anti-malaria drugs such as chloroquine is increasing and spreading geographically. Moreover, anti-malarial drugs are expensive and often unaffordable to low-income populations. A better understanding of the relationship between the El Niño Southern Oscillation (ENSO), the climatic anomalies it engenders, and malaria epidemic could help mitigate the world-wide increase in incidence of this mosquito transmitted disease. There is evidence of a relationship between climate variability and the transmission of mosquito-transmitted diseases. Therefore, in this study we intended to analyze the relationship between ENSO events and annual malaria occurrence (AMO) in Iran to assess the possibility of using ENSO forecasts for improving malaria control. Martials and Methods: Two types of data were used: The data of annual malaria incidence in Iran were collected from the national and international reports of malaria occurrence in Iran; the annual malaria occurrence data for 38 years (1974-2013) were collected from related sources. ENSO is a cyclic phenomenon, which its frequency is 2 to 7 years (i.e., irregular) and is the second strongest natural driver of climate variability, the first being normal seasonal variability. This oscillation has two different phases: a warm episode known as El Niño; and a cold episode called La Niña, where warm and cold refer to the direction of departure from average of the equatorial Pacific Sea surface temperature (SST), a fundamental indicator of the ENSO state. The Pearson correlation analysis at 0.95 confident level (P-value=0.05) on monthly timescale was used in order to understand the relationship between ENSO and annual malaria occurrence in Iran. The 2-tailed independent parametric T-test was used knowing that whether there is a significant difference between the La Nina years occurrence and El Nino years occurrence. Results: The results indicated that a slight negative association could be detected between ENSO and annual Malaria occurrence in Iran. Our finding showed that the detected correlation between monthly ENSO and annual malaria occurrence is statistically significant only in months October and May while no significant relationship between ENSO and AMO at 0.95 confident level was found for other months.. The inverse relationship between ENSO and AMO means that the years having higher malaria occurrence coincides with the warm ENSO phases or EL Nino episode while the years having lower malaria occurrence coincides with the cool ENSO phases or La Nina episode. In El Niño episode, the annual occurrence of malaria is about 0.2 to 0.3 higher than La Niña episode years. Conclusion: The positive association between El Niño and rainfall of Iran resulted in higher occurrence of malaria by proliferation of Anopheles mosquito especially in southern and southeastern region of Iran.

The Madden-Julian Oscillation (MJO) and El Niño Southern Oscillation (ENSO) are known as the primary modes of large-scale climate variability in the equatorial parts of the Indian and Pacific Oceans, respectively. The present study has made an effort to analyze interactions of these two oscillations during boreal autumn and the feedback of these interactions on the occurrence of dry or wet periods in Fars province. Cold and warm phases of ENSO (La Niña and El Niño, respectively) are then classified according to the size of the SOI. Then positive and negative phases of the MJO were defined according to the algebraic sign of the real-time multivariate MJO series 1 (RMM1). Daily values of October-December precipitation data of 9 synoptic stations of Fars province were obtained for the 1974-2013 period. Precipitation amount and the occurrence probability of precipitation were investigated for La Niña, El Niño MJO positive phase, MJO negative phase and other four combinations of these phases. Since the impacts of ENSO or MJO phases on precipitation variability had been studied previously, the present study mainly motivated to investigate precipitation characteristics for the episodes that El Nino or La Nina events were concurrent with the MJO positive phase (El-P or La-P, respectively) or MJO negative phase (El-N and La-N, respectively). The characteristics of atmospheric circulation and vapor transport over the ocean waters and the Middle East are then investigated to justify the obtained results. Some parameters including precipitation, intensity and occurrence probability of a rainy day were computed for all phases, separately. The ratio between these parameters during opposite phases was computed and spatially mapped to evaluate the effects of the interactions. The results indicated that the frequency of the positive and negative MJO phases is significantly associated with the ENSO condition. Differences between the frequency of the positive and negative MJO phases during the El Niño events were found to be insignificant. Contrariwise, during the El Niño events, the frequency and occurrence probability of the positive MJO phase are about twice than corresponding statistics during the MJO negative phase. It was found that ENSO and MJO have a significant influence on autumnal precipitation in Fars province. During El Niño or negative MJO phase, the mean occurrence probability and intensity of precipitation were significantly greater than the corresponding values during La Nina or positive MJO in Fars. For almost entire parts and for the periods of El Nino, precipitation has significantly enhanced or suppressed during the negative and positive MJO phase, respectively. On the other hand, such differences are not significant when the opposite phases of the MJO have concurred with the La Nina events. Compare to El-P, mean precipitation during El-N has increased by about 300% in the southeast and about 70% in the eastern districts. When the El-N phase has prevailed, the autumnal precipitation intensity has increased about 40-110% and 4-40% over the southern and northern area of Fars, respectively. [ABSTRACT FROM AUTHOR]

Background and Aims: Cutaneous leishmaniosis (CL) is a neglected tropical vector-borne disease. As other vector-transmitted diseases, its transmission is sensitive to the physical environment. The purpose of this study was to investigate the relationship between El NiñoSouthern Oscillation (ENSO) and annual incidence of CL in Iran. Materials and Methods: The data of ENSO were obtained from the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center for the period 1977-2011(34 years), and the annual data on CL incidence in Iran from WHO. To determine the association between the ENSO annual fluctuations and annual CL incidence we used crosstab analysis and tow-tailed independent t-test to find any possible differences among the annual CL incidence according to different phases of the Southern Oscillation Index (SOI: El Niño, warming phase; La Niña, cooling phase; neutral phase). Results: Analysis of the data showed that, as compared with the years when El Niño and La Niña were dominant, the annual incidence of CL in Iran was lower in the years when neutral phases of SOI were dominant. The highest incidence was found to have occurred during the years with an intermediate La Niña dominance. During the years when La Nina was dominant the incidence of CL was, on the average, 15-20% higher than that in the years with a neutral phase, while the difference between the annual CL incidence in neutral years and El Niño years was not statistically significant. Conclusion: The findings reveal that in general the mean incidence of cutaneous leishmaniosis during the years with a neutral ENSO index is lower than that during the years with dominant El Nino or La Nina, although there is no difference between incidence in the neutral years and the El Nino-dominant years. [ABSTRACT FROM AUTHOR]

Background and Objective: Malaria is a disease affecting 300-500 million people in tropical and subtropical regions and causes approximately 2.7 million deaths annually. Currently, no vaccine protects against malaria and resistance to anti-malaria drugs such as chloroquine is increasing and spreading geographically. Moreover, anti-malarial drugs are expensive and often unaffordable to low-income populations. A better understanding of the relationship between the El Niño Southern Oscillation (ENSO), the climatic anomalies it engenders, and malaria epidemic could help mitigate the world-wide increase in incidence of this mosquito transmitted disease. There is evidence of a relationship between climate variability and the transmission of mosquito-transmitted diseases. Therefore, in this study we intended to analyze the relationship between ENSO events and annual malaria occurrence (AMO) in Iran to assess the possibility of using ENSO forecasts for improving malaria control. Martials and Methods: Two types of data were used: The data of annual malaria incidence in Iran were collected from the national and international reports of malaria occurrence in Iran; the annual malaria occurrence data for 38 years (1974-2013) were collected from related sources. ENSO is a cyclic phenomenon, which its frequency is 2 to 7 years (i.e., irregular) and is the second strongest natural driver of climate variability, the first being normal seasonal variability. This oscillation has two different phases: a warm episode known as El Niño; and a cold episode called La Niña, where warm and cold refer to the direction of departure from average of the equatorial Pacific Sea surface temperature (SST), a fundamental indicator of the ENSO state. The Pearson correlation analysis at 0.95 confident level (P-value=0.05) on monthly timescale was used in order to understand the relationship between ENSO and annual malaria occurrence in Iran. The 2-tailed independent parametric T-test was used knowing that whether there is a significant difference between the La Nina years occurrence and El Nino years occurrence. Results: The results indicated that a slight negative association could be detected between ENSO and annual Malaria occurrence in Iran. Our finding showed that the detected correlation between monthly ENSO and annual malaria occurrence is statistically significant only in months October and May while no significant relationship between ENSO and AMO at 0.95 confident level was found for other months.. The inverse relationship between ENSO and AMO means that the years having higher malaria occurrence coincides with the warm ENSO phases or EL Nino episode while the years having lower malaria occurrence coincides with the cool ENSO phases or La Nina episode. In El Niño episode, the annual occurrence of malaria is about 0.2 to 0.3 higher than La Niña episode years. Conclusion: The positive association between El Niño and rainfall of Iran resulted in higher occurrence of malaria by proliferation of Anopheles mosquito especially in southern and southeastern region of Iran. [ABSTRACT FROM AUTHOR]