The interrelationship of Plasmodium falciparum and P. vivax in the Punjab

Fox, Emile; Strickland, G. Thomas

doi:10.1016/0035-9203(89)90251-4

Cited by 19 publications

(21 citation statements)

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“…While this appears to have brought about a further reduction in P. vivax prevalence, P. falciparum increased. The free use of CQ might have suppressed P. vivax more than P. falciparum (Clyde 1984;Fox & Strickland 1989). In 2000, the villages were sprayed with deltamethrin, which perhaps caused a sharp decline in malaria incidence.…”

Section: Discussionmentioning

confidence: 99%

Changing scenario of malaria in central India, the replacement of Plasmodium vivax by Plasmodium falciparum (1986–2000)

Singh

Nagpal

Saxena

et al. 2004

Tropical Med Int Health

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Summaryobjectives Since 1986, we have been studying the changing epidemiology of malaria in a forest belt of Mandla, which has the highest number of malaria cases in central India (Madhya Pradesh) to define the epidemiological characteristics of the infection with each Plasmodium species in different seasons of the year. Our long-term objective was to determine the dynamics of Plasmodium vivax vs. P. falciparum infections.methods Five villages underwent fortnightly surveillance of fever cases. Drugs were distributed within 24 h after results of blood smears became available as per Indian National Anti-Malaria Programme. Indoor resting mosquitoes were also collected fortnightly.results The only two Plasmodium species encountered were P. vivax and P. falciparum in both children and adults. Relatively more malaria infections were recorded in children (£14 years) than adults (>14 years) (v 2 ¼ 89.94, P < 0.00001). However, there were significant falling trends in P. vivax from 1986 to 2000 in both age groups (£14 years from 63 to 13, P < 0.0001 and >14 years from 84 to 7, P < 0.0001). The indoor resting density of Anopheles culicifacies, an efficient vector resistant to both dichlorodiphenyltrichloroethane (DDT) (4%) and hexachlorocyclohexane (HCH) (0.4%), was very high throughout this period in all villages (52.35 ± 31.8, range 5-200 per man hour).Anopheles fluviatilis was present in small numbers 0.78 ± 1.24 (range 0-7 per man hour).conclusion Major contributors of the changing epidemiology of malaria in this area are changing drug sensitivity along with insecticide sensitivity.

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Section: Discussionmentioning

confidence: 99%

Changing scenario of malaria in central India, the replacement of Plasmodium vivax by Plasmodium falciparum (1986–2000)

Singh

Nagpal

Saxena

et al. 2004

Tropical Med Int Health

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“…This result is misleading because relapses of vivax malaria from pre-trial infections would occur at equal frequency in insecticide-treated and untreated sectors and could not be distinguished from new infections. The relapse rate is high during the spring in Pakistan, just before the monsoon, and coincides with a growth in anopheline populations (Fox & Strickland 1989;Rowland et al 1997b). The phenomenon of relapse makes it more difficult to eliminate vivax malaria from subtropical areas by vector control compared to falciparum malaria, which does not relapse.…”

Section: Discussionmentioning

confidence: 99%

Indoor residual spraying with alphacypermethrin controls malaria in Pakistan: a community‐randomized trial

Rowland

Mahmood²,

Iqbal³

et al. 2000

Tropical Med Int Health

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SummaryWe conducted a community-randomized controlled trial in Pakistan to determine the efficacy of indoor residual spraying with alphacypermethrin ('Fendona', Cyanamid, NJ, USA), applied at 25 mg/m 2 , to prevent falciparum and vivax malaria. Wettable powder (WP) and suspension concentrate (SC) formulations were tested against an unsprayed control in an irrigated rice-growing area of Sheikhupura district, Punjab province. The study area of 180 km 2 was divided into nine sectors, which were assigned at random to control, WP, or SC treatments in replicates of 3. Sentinel villages were selected from each sector for entomological and disease monitoring. Malaria was monitored by fortnightly active case detection (ACD) and by crosssectional parasite surveys on schoolchildren. Mosquito populations were monitored by space spraying of rooms and by cattle-landing catches. The spray campaign took place in June 1997 and covered 96% of compounds. During the 7 months after spraying, the incidence of falciparum malaria was 95% lower and that of vivax malaria 80% lower in WP-sprayed than unsprayed sectors. Similar results were obtained for sectors sprayed with the SC formulation. Cross-sectional surveys gave estimates of efficacy comparable to those obtained by ACD. Anopheles culicifacies was 80% less abundant and A.stephensi, the predominant anopheline, was up to 68% less abundant in sprayed areas over the 7-month period. Reductions in anopheline parous rates indicated that the single-spray treatment was effective for the entire transmission season. Sprayed surfaces lacked odour, which contributed to the popularity of the campaign. Alphacypermethrin is a promising insecticide for the control of malaria in Pakistan and South Asia generally.

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“…In mixed-species malaria infections of humans, one of the constituent Plasmodium species typically dominates (e.g., Mayne and Young 1938, Molineaux and Grammicia 1980, Looareesuwan et al 1987, Fox and Strickland 1989. Cohen (1973) analyzed the epidemiological literature and reported a general deficit of detectable mixed-species infections, associated this deficit with splenomegaly, and inferred an underlying heterologous immunity.…”

Section: Introductionmentioning

confidence: 99%

“…Recently Dobson (1985Dobson ( , 1990 and Dobson and Roberts (1994) have stressed the role of species life-histories in structuring helminth communities and have extended the general ecological principle that as a constituent species becomes more aggregated in its distribution, the relative importance of interspecific competition declines in its population regulation. Although data on the aggregation of Plasmodium species in Anopheles is essentially anecdotal, its variability indicates that Plasmodium species interactions may warrant more concerted investigation.In mixed-species malaria infections of humans, one of the constituent Plasmodium species typically dominates (e.g., Mayne and Young 1938, Molineaux and Grammicia 1980, Looareesuwan et al 1987, Fox and Strickland 1989. Cohen (1973) analyzed the epidemiological literature and reported a general deficit of detectable mixed-species infections, associated this deficit with splenomegaly, and inferred an underlying heterologous immunity.…”

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confidence: 99%

Mixed-Species Plasmodium Infections of Anopheles (Diptera: Culicidae)

McKenzie

Bossert

1997

Journal of Medical Entomology

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Mixed-pathogen infections of vectors rarely are considered in the epidemiological literature, although they may occur in nature. A review of published reports shows that many Anopheles species are capable of carrying sporozoites of > 1 plasmodium species, of doing so simultaneously in field conditions, and of acquiring and transmitting these in experimental situations. Mixed-species infections in mosquito populations occur at frequencies greater than or equal to the product of the constituent species prevalences, whereas human populations have apparent mixed-species infections at frequencies less than or equal to their corresponding expected values. We present a model for the accumulation of parasite infections over the lifespan of a mosquito that explains this surplus of mixedspecies infections. However, the expected frequencies of mixed infections on the basis of our model are greater than those found in nature, indicating that the sampling by mosquitoes of Plasmodium species from human malaria infections may not be random. KeywordsAnopheles spp; Plasmodium spp; malaria transmission; parasite ecologyThe Pioneering studies of parasite community dynamics have focused on helminths (e.g., Schad 1963, Kennedy 1975, Holmes 1983, Esch et al. 1990. Recently Dobson (1985Dobson ( , 1990 and Dobson and Roberts (1994) have stressed the role of species life-histories in structuring helminth communities and have extended the general ecological principle that as a constituent species becomes more aggregated in its distribution, the relative importance of interspecific competition declines in its population regulation. Although data on the aggregation of Plasmodium species in Anopheles is essentially anecdotal, its variability indicates that Plasmodium species interactions may warrant more concerted investigation.In mixed-species malaria infections of humans, one of the constituent Plasmodium species typically dominates (e.g., Mayne and Young 1938, Molineaux and Grammicia 1980, Looareesuwan et al. 1987, Fox and Strickland 1989. Cohen (1973) analyzed the epidemiological literature and reported a general deficit of detectable mixed-species infections, associated this deficit with splenomegaly, and inferred an underlying heterologous immunity. Hence, the excess of mixed-species infections found during the Carlo project was unexpected, but it also was interpreted as representing species interactions of predominantly cooperative (Cohen and Singer 1979) or predominantly competitive (Molineaux and Grammicia 1980) character. Richie (1988) emphasized competitive interactions in an evolutionary context, suggesting that co-infections promote antigenic divergence, but also proposed a role for mutual facilitation in the ecological succession of Plasmodium species within a mammalian host.Neither the interactions of pathogen species within vectors or the pathogen sampling processes embodied in human-vector contacts have received much attention in the infectious-disease NIH Public Access (Turell et al. 1984, Paulson et al. 1992, V...

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The interrelationship of Plasmodium falciparum and P. vivax in the Punjab

Cited by 19 publications

References 4 publications

Changing scenario of malaria in central India, the replacement of Plasmodium vivax by Plasmodium falciparum (1986–2000)

Changing scenario of malaria in central India, the replacement of Plasmodium vivax by Plasmodium falciparum (1986–2000)

Indoor residual spraying with alphacypermethrin controls malaria in Pakistan: a community‐randomized trial

Mixed-Species Plasmodium Infections of Anopheles (Diptera: Culicidae)

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