Lake Vera revisited: parity and survival rates of Anopheles punctipennis at the site of a malaria outbreak in the Sierra Nevada foothills of California.

Abstract

Abstract. Parity and survival rates of Anopheles punctipennis were studied at the site of a 1952 outbreak of malaria in the Sierra Nevada foothills of California with the purpose of estimating blood feeding frequency and survivorship of such populations. Anopheles punctipennis was the dominant species in landing collections conducted for 20 consecutive nights in August and September 1990. The mean parity rate of An. punctipennis was 0.82. The gonotrophic cycle was estimated to last three days based on time series analysis of the number of nulliparous and parous mosquitoes collected each day. Survivorship was estimated to be 0.79 per gonotrophic cycle and 0.92 per day. Ovarian dilatation data indicated that some females had completed eight gonotrophic cycles prior to being collected and 45% of the females completed two or more cycles. The high prevalence of multiparous individuals, high parity rate, long survivorship and a short three-day gonotrophic cycle estimate indicates that this population is long lived and has a capacity to be an efficient vector of malaria.In 1952, an outbreak of malaria occurred in visitors to summer camps and residences at Lake Vera in the foothills of the Sierra Nevada in California. This outbreak was remarkable in that a single infected individual spent a weekend at the lake and served as the source for 35 subsequent cases. 1, 2 This suggested that one or more Anopheles species at Lake Vera were highly efficient vectors. Both An. punctipennis and An. freeborni were abundant when the outbreak was investigated in late August 1952. 3, 4 Although An. freeborni has been considered the principle vector of Plasmodium vivax malaria in western North America, 5 An. punctipennis, a vector of minor importance, 5, 6 may have played a prominent role in transmitting malaria during the 1952 outbreak. 3,4,7,8 During the 1980s, additional cases of mosquito-borne autochthonous malaria occurred in California in areas where An. punctipennis was abundant and An. freeborni were few or absent and where available larval habitat was more typically associated with the larvae of An. punctipennis than An. freeborni. 9,10 In spite of the potential role of An. punctipennis as a malaria vector, little is known about its biology; particularly, factors that contribute significantly to its biological capacity to serve as a vector including adult female survivorship, abundance, blood feeding frequency, and host range. 11 The objective of the current study was to study the survivorship of anophelines at Lake Vera and determine which species were using potential larval habitats and would be attracted to potential human hosts. MATERIALS AND METHODSStudy site. Lake Vera is a small artificial lake 10 km north of Nevada City in Nevada County, California. The lake is located in a transitional forest consisting of Ponderosa pine, incense cedar, live oak, and manzanita at an elevation of 800 m on the west slope of the Sierra Nevada. 2-4 Lake Vera was shallow at the time of this study and approximately 30% of the surface was cov...

Comparison of Different Sampling Methods to Catch Lymphatic Filariasis Vectors in a Sudan Savannah Area of Mali

“…The high parity and survival rates of mosquitoes captured with these two methods indicate the suitability of the collected fauna for transmission assessment. 39,40 In terms of infected mosquito identification, HLC showed a higher MIPL for P. falciparum in Bougoula as compared with the ITTC. For W. bancrofti and in the village of Boundioba, the collection methods were still comparable with respect to the MIPL overlapping 95% CI.…”

The new Internal Transcribed Spacer 2 diagnostic tool clarifies the taxonomic position and geographic distribution of the North American malaria vector Anopheles punctipennis

“…Three species are considered dominant malaria vectors in North America-Anopheles freeborni, Anopheles pseudopunctipennis, and Anopheles quadrimaculatus [6]. In addition to these species, Anopheles punctipennis, the most common and widely distributed anopheline mosquito species in North America [7], was an important contributor to malaria transmission in the USA in the past [8]. Similar to An.…”

The New Internal Transcribed Spacer 2 Diagnostic Tool Clarifies the Taxonomic Position and Geographic Distribution of the North American Malaria Vector Anopheles Punctipennis

“…In addition to these species, An. punctipennis, Say, the most common and widely distributed anopheline mosquito species in North America [7], was an important contributor to malaria transmission in the US in the past [8]. Similar to An.…”