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French dogs at risk in Réunion Island
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News & Comment
turning the immune system of a six-month old into that of a six-year old,’ said Adrian Hill, principal investigator of the project at the University of Oxford. JVC
NO means NO A hitherto unrecognized role for nitric oxide (NO) in innervation of trematodes has been discovered, suggesting that NO is an old signal molecule in evolutionary scale. N. Saha and co-workers found evidence of NO synthesis in the neuronal cell bodies in two cerebral ganglia, the brain commisure and the nerve fibers, in the main nerve cords of the digenetic trematode Fasciolopsis buski [(2001) Parasitol. Int. 50, 157–163]. The innervation of the pharynx, the cirrus sac, the ventral sucker and other nerve tributaries of the general parenchyma also showed evidence of NO synthesis. NADPH diaphorase expression was used as a histochemical marker for NO synthase activity. Biochemically active NO was also detected at the level of the whole organism, suggesting that parasite-derived NO might have consequences for host physiology. SHK
French dogs at risk in Réunion Island Results from two Merial-sponsored epidemiological reports presented at the 18th International Conference of the World Association for the Advancement of
TRENDS in Parasitology Vol.17 No.12 December 2001
Veterinary Parasitology in Stresa, Italy, suggested that French tourists who travel with companion animals to the Réunion Island risk importing canine ehrlichiosis and canine spirocercosis into Europe. Frédéric Beugnet (Europe for Merial Companion Animal Global Enterprise, France) demonstrated that ehrlichiosis prevalence in Réunion Island was 22.7% among dogs attending vet clinics, but 59.5% among stray dogs. In addition, 4.8% of symptomatic dogs attending vet clinics were infected with Spirocerca lupi. Most infected dogs were <3 years old, whereas tumours were generally diagnosed in older dogs (~7 years old). However, it was also found that 61.5% of stray dogs and 27.5% of asymptomatic dogs attending vet clinics were infected. Beugnet said that both studies indicated the role for the stray dog population as a reservoir for the agents. MH
A lesson in mitochondria André Schneider has published an interesting account of mitochondrial biogenesis (MB) in trypanosomatids [(2001) Int. J. Parasitol. 31, 1403–1415]. MB consists of the processes required for mitochondrial membrane formation (and the soluble compartments they contain), mitochondrial genome replication and correct segregation of the organelles during cell division. Trypanosomatids belong to the earliest diverging branches of the eukaryotic tree that have mitochondria and are fascinating
in an evolutionary sense. The expression of proteins encoded on the mitochondrial genome of trypanosomatids involves a complex and unique series of processes. Many genes represent incomplete open reading frames, and their primary transcripts are remodeled into translatable messenger RNAs by RNA editing. This process is mediated by small mitochondriaencoded transcripts called guide-RNAs, which are specific to trypanosomatids and closely related organisms. Similarly, mitochondrial translation in trypanosomatids is unconventional and involves imported cytosolic, eukaryotictype transfer RNAs. The mitochondrial ribosomes contain the smallest known ribosomal RNAs, ~30% shorter than the already reduced ribosomal RNAs in human mitochondria. Furthermore, some trypanosomatids have life cycle stages exhibiting different mitochondrial activities and can, therefore, serve as a model system for the regulation of mitochondrial biogenesis. SHK Sarah Hudson Keenihan ([email protected]) Theo Schetters ([email protected]) Michael Holland ([email protected]) Lydia Leonardo ([email protected]) Jayne V. Carey ([email protected])
Letters
Rising temperature and the malaria epidemic in Burundi Burundi and the neighbouring countries are experiencing the effects of an increased intensity in malaria transmission1. Rising morbidity and mortality rates are being reported throughout Burundi, where Plasmodium falciparum accounts for the vast majority of cases2. The Hospital of Kiremba (Ngozi province, Burundi) is a 140-bed facility sited at 1540 m above sea level (asl) in the highlands of Burundi, which serves 75 000 people residing in a valley with altitudes ranging from 1200–1800 m asl. http://parasites.trends.com
Since 1992, all blood slides screened for malaria were recorded with clinical findings of malaria. According to the hospital registry, a four-fold increase in microscopic diagnoses of malaria was recorded between January 1999 (n = 1362) and January 2001 (n = 5475). Increased profound anaemia (mean haemoglobin levels fell from 7.9 g dl-1 in 1996 to 4.6 g dl-1 in 2001 in malaria patients), higher splenomegaly rates (from 28% in 1996 to 79% in 2001) and a lower proportion of patients aged ≥14 years (28% in 1996 to 8.7% in 2001) were recorded from malaria patients residing at altitudes <1450 m asl, where malaria has been endemic in the past 30 years (based on the records concerning patients’ domicile). In this geographically defined group, only 2.8% of malaria admissions
are now classified as cerebral malaria (7.1% in 1996), and most current mortality results from concurrent illnesses (e.g. pneumonia and sepsis). Gametocyte carriage on admission increased from 8% in 1996 to 40% in 2001. A different picture is seen with patients living in areas between 1450–1650 m asl where malaria transmission did not occur until 1999. After 1999, an increasing number of cases were diagnosed from patients residing at altitudes up to 1650 m asl: anaemia and splenomegaly are rare, cerebral malaria accounts for 9% of all malaria admissions and 38% of malaria patients are aged ≥14 years. This indicates an increased transmission of malaria in lowland areas and a recent introduction of the disease in previously disease-free areas3. Climatic data also suggest
1471-4922/01/$ – see front matter © 2001 Elsevier Science Ltd. All rights reserved.
News & Comment
turning the immune system of a six-month old into that of a six-year old,’ said Adrian Hill, principal investigator of the project at the University of Oxford. JVC
NO means NO A hitherto unrecognized role for nitric oxide (NO) in innervation of trematodes has been discovered, suggesting that NO is an old signal molecule in evolutionary scale. N. Saha and co-workers found evidence of NO synthesis in the neuronal cell bodies in two cerebral ganglia, the brain commisure and the nerve fibers, in the main nerve cords of the digenetic trematode Fasciolopsis buski [(2001) Parasitol. Int. 50, 157–163]. The innervation of the pharynx, the cirrus sac, the ventral sucker and other nerve tributaries of the general parenchyma also showed evidence of NO synthesis. NADPH diaphorase expression was used as a histochemical marker for NO synthase activity. Biochemically active NO was also detected at the level of the whole organism, suggesting that parasite-derived NO might have consequences for host physiology. SHK
French dogs at risk in Réunion Island Results from two Merial-sponsored epidemiological reports presented at the 18th International Conference of the World Association for the Advancement of
TRENDS in Parasitology Vol.17 No.12 December 2001
Veterinary Parasitology in Stresa, Italy, suggested that French tourists who travel with companion animals to the Réunion Island risk importing canine ehrlichiosis and canine spirocercosis into Europe. Frédéric Beugnet (Europe for Merial Companion Animal Global Enterprise, France) demonstrated that ehrlichiosis prevalence in Réunion Island was 22.7% among dogs attending vet clinics, but 59.5% among stray dogs. In addition, 4.8% of symptomatic dogs attending vet clinics were infected with Spirocerca lupi. Most infected dogs were <3 years old, whereas tumours were generally diagnosed in older dogs (~7 years old). However, it was also found that 61.5% of stray dogs and 27.5% of asymptomatic dogs attending vet clinics were infected. Beugnet said that both studies indicated the role for the stray dog population as a reservoir for the agents. MH
A lesson in mitochondria André Schneider has published an interesting account of mitochondrial biogenesis (MB) in trypanosomatids [(2001) Int. J. Parasitol. 31, 1403–1415]. MB consists of the processes required for mitochondrial membrane formation (and the soluble compartments they contain), mitochondrial genome replication and correct segregation of the organelles during cell division. Trypanosomatids belong to the earliest diverging branches of the eukaryotic tree that have mitochondria and are fascinating
in an evolutionary sense. The expression of proteins encoded on the mitochondrial genome of trypanosomatids involves a complex and unique series of processes. Many genes represent incomplete open reading frames, and their primary transcripts are remodeled into translatable messenger RNAs by RNA editing. This process is mediated by small mitochondriaencoded transcripts called guide-RNAs, which are specific to trypanosomatids and closely related organisms. Similarly, mitochondrial translation in trypanosomatids is unconventional and involves imported cytosolic, eukaryotictype transfer RNAs. The mitochondrial ribosomes contain the smallest known ribosomal RNAs, ~30% shorter than the already reduced ribosomal RNAs in human mitochondria. Furthermore, some trypanosomatids have life cycle stages exhibiting different mitochondrial activities and can, therefore, serve as a model system for the regulation of mitochondrial biogenesis. SHK Sarah Hudson Keenihan ([email protected]) Theo Schetters ([email protected]) Michael Holland ([email protected]) Lydia Leonardo ([email protected]) Jayne V. Carey ([email protected])
Letters
Rising temperature and the malaria epidemic in Burundi Burundi and the neighbouring countries are experiencing the effects of an increased intensity in malaria transmission1. Rising morbidity and mortality rates are being reported throughout Burundi, where Plasmodium falciparum accounts for the vast majority of cases2. The Hospital of Kiremba (Ngozi province, Burundi) is a 140-bed facility sited at 1540 m above sea level (asl) in the highlands of Burundi, which serves 75 000 people residing in a valley with altitudes ranging from 1200–1800 m asl. http://parasites.trends.com
Since 1992, all blood slides screened for malaria were recorded with clinical findings of malaria. According to the hospital registry, a four-fold increase in microscopic diagnoses of malaria was recorded between January 1999 (n = 1362) and January 2001 (n = 5475). Increased profound anaemia (mean haemoglobin levels fell from 7.9 g dl-1 in 1996 to 4.6 g dl-1 in 2001 in malaria patients), higher splenomegaly rates (from 28% in 1996 to 79% in 2001) and a lower proportion of patients aged ≥14 years (28% in 1996 to 8.7% in 2001) were recorded from malaria patients residing at altitudes <1450 m asl, where malaria has been endemic in the past 30 years (based on the records concerning patients’ domicile). In this geographically defined group, only 2.8% of malaria admissions
are now classified as cerebral malaria (7.1% in 1996), and most current mortality results from concurrent illnesses (e.g. pneumonia and sepsis). Gametocyte carriage on admission increased from 8% in 1996 to 40% in 2001. A different picture is seen with patients living in areas between 1450–1650 m asl where malaria transmission did not occur until 1999. After 1999, an increasing number of cases were diagnosed from patients residing at altitudes up to 1650 m asl: anaemia and splenomegaly are rare, cerebral malaria accounts for 9% of all malaria admissions and 38% of malaria patients are aged ≥14 years. This indicates an increased transmission of malaria in lowland areas and a recent introduction of the disease in previously disease-free areas3. Climatic data also suggest
1471-4922/01/$ – see front matter © 2001 Elsevier Science Ltd. All rights reserved.