Malaria vectors in the changing environment of the southern Punjab, Pakistan

The Pakistani Punjab experienced several devastating malaria epidemics during the twentieth century. Since the 1980s, however, malaria has been at a low ebb, while in other areas of Pakistan and neighbouring India malaria is on the increase. This raises the question of whether transmission in the Pakistani Punjab may have been influenced by a change in vector species abundance or composition, possibly induced by environmental changes. To investigate this question, routinely-collected government entomological data for the period 1970 to 1999 for the district of Bahawalnagar, in the Indus Basin irrigation system in the southern Punjab, was analysed. Our findings suggest that Anopheles stephensi has increased in prevalence and became more common than A. culicifacies during the 1980s. This shift in species dominance may be due to the large-scale ecological changes that have taken place in the Punjab, where irrigation-induced waterlogging of soil with related salinization has created an environment favourable for the more salt-tolerant A. stephensi. Some biotypes of A. stephensi are suspected of being less efficient vectors and, therefore, the shift in species dominance might have played a role in the reduced transmission in the Punjab, although further research is needed to investigate the effect of other transmission-influencing factors.     

Molecular Detection of Malaria in South Punjab with Higher Proportion of Mixed Infections

Background

Malaria is well known for its fatalities worldwide, Plasmodium vivax and the Plasmodium falciparum are the two important species of malaria reported from Pakistan and creating lots of morbidities across the country.

Method

Study was conducted to determine the Surveillance of malaria in South Punjab by microscopy and Polymerase chain reaction (PCR).

Result

samples out of 100 patients were found positive for malarial parasites. One patient was found with mixed infection, whereas P. falciparum and P. vivax infections were detected in 17 and 22 patients, respectively. In nested PCR, genus-specific primers for Plasmodium species. in round 1 and species-specific primers for P. falciparum and P. vivax in round 2 were used. By the application of PCR 41% were found to be infected by Plasmodium spp. Among Plasmodium positive patients: mixed, P. falciparum and P. vivax infection were detected in 10, 15 and 16 patients, respectively. Thirty nine microscopically positive patients confirmed to have Plasmodium spp. One negative by PCR, 2 microscopically negative patients had shown Plasmodium spp. infection (P. falciparum and P. vivax) by PCR. In total samples, P. falciparum, P. vivax and mixed infection accounted for 36.6%, 39.0% and 24.3%, respectively.

Conclusion

Microscopy was found deficient for interpretation of mixed infections, low parasitaemia, and species specific diagnosis. The sensitivity, specificity and efficacy of nested PCR was calculated 95%, 98% and 97%, respectively, showing PCR as a more effective and efficient diagnostic tool for malaria.     

Massive splenomegaly in Northern Zambia. II. Schistosomal splenomegaly and elevated IgG

Twenty-three patients from Northern Zambia with massive splenomegaly due to chronic schistosomiasis were studied. The mean serum IgG levels were found to be extremely high compared with local blood donors and local patients with Tropical Splenomegaly Syndrome (TSS). Mean serum IgG levels also appear to be higher in Zambians with schistosomal splenomegaly than in those reported in patients from most other areas. Mean IgM levels of patients with schistosomal splenomegaly were higher than those of local blood donors, but not as high as in the TSS. IgG and IgM estimations are sometimes of value in the differential diagnosis of splenomegaly in the tropics.     

Idiopathic splenomegaly in Iran

During the past 5 years we have investigated 45 patients with the clinical manifestations suggestive of cirrhosis. We found 40 of them having cirrhosis but 3 patients had idiopathic splenomegaly. They underwent splenctomy and after 1-5 years they have remained free of the disease.     

Metabolism of IgM in the tropical splenomegaly syndrome

IgM metabolism was studied in five patients with the tropical splenomegaly syndrome and in five controls. The half-life and turnover time of I¹²⁵ IgM was similar in the two groups. We conclude that the raised serum IgM levels found in patients with the tropical splenomegaly syndrome are not due to decreased IgM catabolism but are due to increased IgM production.     

Dyspnea, pancytopenia, and splenomegaly

An extensive initial laboratory assessment, including testing for viral disorders, left the diagnosis unsolved.     

Malaria and the mud lobster

Effective control of the mud lobster (Thalassina anomala) has been achieved by pouring a $\text{1}\text{4}$ to $\text{1}\text{2}$ a gallon of a mixture of lime and water (5 pounds to 3 gallons) down the holes and then ramming in sand. This method kills the animals and will free an area from them if conscientiously applied. The area is not, of course, rendered immune from re-invasion and periodical inspection and treatment of new holes round the margins of the area must be carried out.A layer of the fibrous material formed on the trunks of cocoanut trees by the withering of the leaf bases, soaked in tar and buried 1 foot deep in tidal bunds will prevent the mud lobsters from burrowing up through the bunds.The use of the term “crab-holes” for the burrows should be discontinued, as it suggests that they are made by the large crabs which frequent them. The responsible animal is the mud lobster and the term “mud-lobster holes” or simply “lobster-holes” is a suitable one.     

Ultrastructure of the hepatic sinusoids in the tropical splenomegaly syndrome

In Ugandan cases of TSS electron microscopy shows that the hepatic sinusoids are filled by Küpffer cells and lymphocytes. The Kupffer cells are both hyperplastic and hypertrophied, much of the latter being due to extensive proliferation of their surface membranes similar to that of antigen trapping dendritic macrophages from germinal centres. The membrane extensions are apparently functioning as a trapping zone which accumulates an electron-dense deposit on the cell surface. There is no evidence that this deposit is taken up into the cell. A group of cells described here as M cells, though basically similar to Kupffer cells, lack many of the Kupffer cell characteristics and in particular the extensive plasma membrane development. Such cells show considerable evidence of uptake of material via large coated vesicles and have fewer mitochondria and less endoplasmic reticulum than the Kupffer cells. They probably represent a different functional development from the Kupffer cells or possibly from a common stem cell. Many of the lymphocytes show, by their ribosome content, expanded perinuclear space, and increased numbers of endoplasmic reticulum elements and mitochondria, that they are not small lymphocytes but are of the activated lymphocyte series.The general appearance is consistent with a complex immunological reaction occurring in the liver sinusoids.