Inactivation of Plasmodium spp. in plasma and platelet concentrates using riboflavin and ultraviolet light.

BACKGROUND: Photochemical treatment of blood products could help prevent transfusion-transmitted malaria and reduce the need for donor deferrals. In this study we evaluated the effectiveness of riboflavin and ultraviolet (UV) light against both Plasmodium falciparum, which causes the most severe form of human malaria, and Plasmodium yoelii, an in vivo murine model for malaria. STUDY DESIGN AND METHODS: Plasma and platelet (PLT) concentrates were inoculated with either P. falciparum- or P. yoelii-infected red blood cells (RBCs). Aliquots from each unit were collected after inoculation, after addition of riboflavin, and after treatment. In vitro P. falciparum growth was assessed using thin blood films of duplicate samples at 24, 48, 72, and 96 hours. P. yoelii parasitemia was followed in mice for 14 days postinoculation. RESULTS: In the in vitro studies, the mean P. falciparum parasitemia increased 12- to 19-fold in pretreatment samples, both before and after addition of riboflavin, after 96-hour culture. Few parasites were observed in Mirasol-treated units at 24 hours; those that were observed were degenerating. Through the remainder of the 96-hour culture period, cultures of treated samples were negative. In the in vivo study, mouse plasma containing P. yoelii-infected RBCs had a mean starting titer of 4.6 log mouse infectious dose 50%/mL. No infectious parasite was detected in treated samples. CONCLUSION: Treatment with riboflavin and UV light was effective at reducing viable P. falciparum in both PLT and plasma products by at least 3.2 logs. Additionally, an at least 4.4-log reduction was observed with P. yoelii.

Adaptation of a multi-drug resistant strain of Plasmodium falciparum from Peru to Aotus lemurinus griseimembra, A. nancymaae, and A. vociferans monkeys.

A strain of Plasmodium falciparum from Peru was adapted to splenectomized Aotus nancymaae and Aotus vociferans monkeys. The Peru 134/CDC strain of P. falciparum was shown to be resistant to treatment with chloroquine in monkeys and partially resistant to mefloquine and malarone. Genetic mutations in crt, dhfr, dhps, and cytochrome b genes conferring drug resistance were also determined for this Peruvian strain of P. falciparum.

PCR-based detection of Angiostrongylus cantonensis in tissue and mucus secretions from molluscan hosts.

Angiostrongylus cantonensis is a common cause of human eosinophilic meningitis. Recent outbreaks of this infection have shown that there is a need to determine the distribution of this nematode in the environment in order to control transmission. A. cantonensis is generally identified morphologically in the molluscan intermediate host by microscopic examination, which can be labor-intensive. The aim of this study was to develop a PCR-based method to detect A. cantonensis directly from molluscan tissue. A total of 34 Parmarion cf. martensi (Simroth) semislugs, 25 of which were naturally infected with A. cantonensis, were used to develop this assay. Tissue pieces (approximately 25 mg) were digested with pepsin-HCl to recover third-stage larvae for morphological identification or were used for DNA extraction. PCR primers were designed to amplify 1,134 bp from the Angiostrongylus 18S rRNA gene, and the amplicons produced were sequenced for identification at the species level. Both microscopy and the PCR-DNA sequencing analysis indicated that the same 25 semislugs were positive for A. cantonensis, showing that the two methods were equally sensitive and specific for this application. However, morphological detection requires access to living mollusks, whereas molecular analysis can also be performed with frozen tissue. The PCR-DNA sequencing method was further evaluated using tissue from Veronicella cubensis (Pfeiffer) slugs and mucus secretions from infected P. martensi. To our knowledge, this is the first use of a PCR-based method to confirm the presence of A. cantonensis in mollusks collected in the environment.

Observations on the exoerythrocytic stages of different isolates of Plasmodium cynomolgi in hepatocytes of New World aotus and Saimiri monkeys.

Sporozoites of 3 isolates of Plasmodium cynomolgi dissected from the salivary glands of Anopheles dirus and Anopheles quadrimaculatus were injected intravenously into 9 New World monkeys. Liver stage parasites were demonstrated in all 9 animals; 7 of these animals also produced blood stages after prepatent periods of 9 to 23 days.

Infection of Saimiri boliviensis monkeys with Plasmodium coatneyi.

Abundant, apparently normally developing, liver-stage parasites of Plasmodium coatneyi were demonstrated following injection of sporozoites dissected from the salivary glands of Anopheles dirus mosquitoes. Erythrocytic development was not demonstrated.

Adaptation of a strain of Plasmodium falciparum from Ghana to Aotus lemurinus griseimembra, A. nancymai, and A. vociferans monkeys.

A strain of Plasmodium falciparum from Ghana was adapted to Aotus lemurinus griseimembra, A. nancymai, and A. vociferans monkeys. Gametocytes in splenectomized A. nancymai were infective to Anopheles freeborni mosquitoes. Sporozoite transmission was accomplished in two splenectomized A. nancymai with prepatent periods of 22 and 25 days. The Ghana III/CDC strain of P. falciparum is susceptible to treatment with chloroquine and mefloquine.

Cultivation of clinically significant hemoflagellates.

The hemoflagellates, Trypanosoma spp. and Leishmania spp., are causal agents of a number of parasitic diseases having a major impact on humans and domestic animals over vast areas of the globe. Among the diseases are some of the most pernicious and deadly of human afflictions: African sleeping sickness, Chagas' disease, kala-azar, and Oriental sore. The organisms have complex, pleomorphic life cycles typically involving a vertebrate and an invertebrate host, the latter serving as a vector. In the vertebrate host, they are primarily blood and tissue parasites. In their transition from one host to another, the hemoflagellates undergo morphological, physiological, and biochemical changes that facilitate their growth and subsequent transmission. A major goal in the study of the hemoflagellates has been the cultivation in vitro of both vertebrate and invertebrate stages of the organisms. The first types of media used in their cultivation, and still useful for establishment of cultures, were undefined and contained a complex of ingredients. These gave way to semidefined formulations which included tissue culture media as a base and, as a next step, addition of tissue culture cells as a feeder layer to promote parasite growth. More recently developed media are completely defined, having replaced the feeder cells with various supplements. Serum, a sometimes-variable component of the media, can be replaced by various serum substitutes. This review focuses on the hemoflagellates that infect humans, describing stages in the development of media leading to the fully defined formulations that are now available for the cultivation of many of these organisms.

Experimental infection of Anopheles farauti with different species of Plasmodium.

Studies were conducted to determine the susceptibility of Anopheles farauti to different species and strains of Plasmodium. Mosquitoes were infected by feeding on animals or cultures infected with different strains of P. vivax, P. falciparum, P. ovale, P. coatneyi, P. gonderi, P. simiovale, P. knowlesi, and P. brasilianum. Infections of P. vivax and P. coatneyi were transmitted via sporozoites from An. farauti to monkeys. Comparative infection studies indicated that An. farauti was less susceptible to infection than An. stephensi, An. gambiae, An. freeborni, and An. dirus with the Salvador I strain of P. vivax, but more susceptible than An. stephensi and An. gambiae to infection with the coindigenous Indonesian XIX strain.

Enzootic Angiostrongylus cantonensis in rats and snails after an outbreak of human eosinophilic meningitis, Jamaica.

After an outbreak in 2000 of eosinophilic meningitis in tourists to Jamaica, we looked for Angiostrongylus cantonensis in rats and snails on the island. Overall, 22% (24/109) of rats harbored adult worms, and 8% (4/48) of snails harbored A. cantonensis larvae. This report is the first of enzootic A. cantonensis infection in Jamaica, providing evidence that this parasite is likely to cause human cases of eosinophilic meningitis.

Report of ezootic Angiostronglyus cantonesis from Jamaica [ABSTRACT]

OBJECTIVE: To study the status of infection with Angiostrongylus cantonensis in wild rats and snails in Jamaica following an outbreak of eosinophilic meningitis amongst tourists. METHODS: One hundred and thirty-one Rattus rattus and 94 R norvegicus were collected, mainly from the eastern portion of Jamaica. The animals were dissected and the heart and pulmonary arteries explored to reveal A cantonensis. Similarly, several species of land snails were collected. A portion of the head/foot was excised, fragmented and placed in separate dishes of digestion fluid (0.01 percent pepsin in 0.7 percent v/v aqeous HCI). Dishes were examined for nematode larvae 4-5 hours and 24 hours post-digestion. A microscopical comparison of larvae with museum specimens confirmed identification. RESULTS: Overall, significantly more R rattus (42.7 percent) than R morvegicus (21.3 percent) were infected (x2=11.28;p<0.0001). Considering only those parishes where 15 or more rats were collected (Hanover, Manchester, St.James, St. Elizabeth, Kingston and St.Andrew, and Portland) the prevalence of rodent infections ranged from 6 to 59 percent. Of three snails and one slug species collected, only Thelidomus asper harboured A cantonensis larvae. This snail was collected from Manchester where the highest prevalence of rodent infections also occurred. CONCLUSIONS: The findings indicate that A cantonensis is present in rats and snails in Jamaica. In the context of reports (1996, 2000) of eosinophilic meningitis on the island, we recommend that public health officials, clinical parasitologists and travel medicine practitioners consider A cantonensis as a causative agent of eosinophilic meningitis in residents and travellers to Jamaica. (AU)

Predation on peridomestic mosquitoes by hylid tadpoles on Grand Bahamas Island

In order to determine whether tadpoles of Hyla septentrionalis are effective predators of larval peridomestic mosquitoes, larvae were exposed to tadpoles and the association between larvae and tadpoles in nature was recorded. Tadpoles were cannibalistic, eating egg masses of their own species, as well as a variety of material of both plant and animal origin. Tadpoles captured and ate more than 13 larval Culex pipiens per day. In natural breeding sites on Grand Bahamas Island, larval C. papiens were never abundant in sites that contained tadpoles and when tadpoles were introduced into vessels that contained mosquitoes, these containers soon became free of mosquitoes. The habitat of H. septentrionlis tadpoles in the study area seemed identical to that of larval C. papiens and more than half of apparently suitable sites contained tadpoles. Thus, the presence of these frogs appeared to limit the abundance of C. papiens.(AU)